Chemistry Grade 9 Notes

Chemistry - Chapter 5 Review Questions

Properties and Changes

P188 Review Questions

1) What is the difference between each of the following terms?

a. Heterogeneous (Mechanical) Mixture – particles not uniformly scattered. Ex: sugar and salt,

sand and water

Homogeneous Mixture – particles are uniformly scattered throughout at all microscopic levels.

Ex: stainless steel, steel, alloys, solutions, pure substances

b. Quantitative Property – a characteristic of a substance that can be measured numerically. Ex:

density, mass, weight

Qualitative Property – a characteristic of a substance that can be described but not measured. Ex:

colour, physical state, texture

c. Suspension – particles may be seen with the naked eye or with a weak microscope. If left

undisturbed, gravity will cause the suspended particles to separate. Ex: magnesia in milk

Colloid – appears homogeneous, but is heterogeneous, very similar to solutions. Contains very

tiny particles that do not separate when undisturbed. Colloids scatter light, known as the Tyndall

Effect. Ex: jelly, butter, whipped cream

d. Element – a pure substance made up of one type of atom. Each element has its own distinct

properties and cannot be broken down, destroyed or created. Ex: hydrogen, lead, gold, iron

Compound – A combination of 2 or more elements in definite proportions, a compound is a pure

substance. Ex: water, salt, sugar, air

4) If a substance undergoes a physical change, will there be a change in its chemical properties? If

a substance undergoes a chemical change, will there be a change in its physical properties?

During a physical change, there is no change in a substance’s chemical properties because the

chemical composition of the starting substance has not changed, and no new substance has been

created.

During a chemical change, there will likely be a change in its physical properties because during

a chemical change, a new substance is formed and its composition and arrangement of elements

has changed.

8) What is the difference between a physical and chemical property? Give examples of each

property to describe oxygen gas.

Physical Property – a property that can be observed or measured without forming a new

substance. Oxygen is a gas, is colourless, has no odour, and is transparent

Chemical Property – a property that describes how a substance reacts with another substance

when forming a new substance. Oxygen supports combustion and combines with most elements.

10) Distinguish between physical and chemical change, state indicators of chemical change.

A physical change does not create a new substance and can be reversed; a chemical change

creates a new substance and is very hard to reverse. Some indicators of chemical changes are:

exothermic or endothermic reaction, a change in colour, a material with new properties forms, or

gas bubbles from a liquid.

11) Classify as a physical or chemical change (not sure if these are right)

Physical Change Chemical Change

Percolating Coffee

Letting Paint Dry Frying an Egg

Toasting Bread

Letting Cement Settle

Growing a Plaint

12) Classify in the following categories

Element Compound Solution Suspension Mech. Mix Colloid

- Mercury

- Copper - Sand

- 18 karat gold

- 2$ Coin - Muddy water - Egg

- Compost - Hair conditioner

- Fog

15) Similarities and Differences between the Particle Theory and Dalton’s Atomic Theory.

Both are very similar, but Dalton’s is more in depth. Dalton’s atomic theory names the tiny

particles atoms, and distinguishes pure substances as elements, atoms that cannot be broken

down, destroyed, or split and are identical, or compounds which are a combination of elements.

Chemistry - Chapter 6 Review Questions and Notes

Meet the Elements

P192 Symbols for the Elements

Modern Symbols invented by Jons Jacob Berzelius (1779 – 1848). The uses for symbols are:

To be able to communicate scientifically worldwide, throughout different languages

Used as a short form for writing out chemical formulas

P194 Understanding Formulas for Compounds

A Chemical Formula uses symbols and numerals to represent the composition of pure substances.

Ex: The chemical formula for water (H2O) represents

The composition of pure water wherever it is found

The composition of a molecule of water

A Molecule is the smallest independent unit of a compound and is generally a cluster of atoms

bounded together.

P203 Different Kinds of Elements

Type of Element State at Room Temp. Appearance Conductivity Malleability and Ductility

Examples

Metals Solid

(except Mercury liquid) Shiny Lustre Good conductors of heat and electricity Malleable and

Ductile (can be hammered and stretched) Lithium

Beryllium

Gold

Silver

Nonmetals Solids and Gases

(except Bromine liquid) Dull, not Shiny Poor conductors of heat and electricity Brittle and Not

Ductile (can’t be shaped or stretched) Nitrogen

Oxygen

Radon

Hydrogen

Metalloids Solid Shiny or Dull May conduct electricity, Poor heat conductors Brittle and Not

Ductile (can’t be shaped or stretched) Boron

Silicon

Arsenic

Polonium

P210 The Story of Aluminum

Aluminum was abundant, but was hard to use efficiently because:

A coating of Aluminum Oxide (Al2O3) always forms on the surface of pure Aluminum

Aluminum Oxide is strongly bound and hard to decompose

Electrolysis only works on liquids, either pure substances or solutions

Aluminum Oxide is a Solid, melting it is impractical

Does not dissolve in any common liquid

In 1886, Charles Martin Hall and Paul Lois Hérolt solved the problem. They used hot, melted

Cryolite (Aluminum Sodium Fluoride, Na3AlF6) as a solvent for powdered aluminum oxide,

which dissolves it. Applying a strong electric current decomposes the oxide, and it can be

collected at the bottom of the container.

P217 Mendeleev Builds a Table

Russian chemist Dmitri Mendeleev (1834-1907) arranged the elements in a Periodic Table by

noticing the repeating properties at set intervals. Gaps were left in the table for undiscovered

elements. There were no noble gases discovered at the time.

P222 Characteristics of Interesting Groups

Alkali Metals - React rapidly when exposed to air and water

- Most reactive metals

- Have 1 Valence Electron

- Reactivity increases downwards, reactivity decreases going right

Halogens - 7 Valence Electrons

- Reactivity decreases downwards, reactivity increases going right

- Highly Reactive Nonmetals

- Chlorine and Iodine used as disinfectants that kill bacteria

- Fluorine is highly reactive with glass

Nobel Gases - Very Stable, rarely react with any other elements

- Have maximum number of Valence Electrons

- Odourless and Colourless

- Emit a colour when electricity is passed through


2) What information is represented in a chemical formula?

Which elements are found in the substance, to what proportions, and the number of atoms of each

element present in a molecule.

4) Which elements are referred to as coinage metals?

Copper (Cu), Silver (Ag) and Gold (Au) are referred to as coinage metals.

5) Write the Name and Symbol of a metal and non-metal that are liquids at room temperature.

Mercury (Hg) is a metal that is liquid at room temperature and Bromine (Br) is a nonmetal that is

liquid at room temperature.

15) How did Mendeleev organize the elements in his periodic table? In this chapter, you learned

two elements that were unknown but predicted by Mendeleev, name the two elements.

Mendeleev organized his table in order of increasing atomic mass, and making columns of

elements with similar properties, which occurred at periodic intervals. Two unknown elements

predicted by Mendeleev because of examining the properties of known atoms are Gallium (Ga)

and Germanium (Ge). No noble gases were represented in his table as they were undiscovered.

16) Why is the modern day periodic table one of the foundations of modern day chemistry?

The modern day periodic table clearly shows the characteristics of all the elements. The periodic

table displays which elements are alike, the order of mass of the elements, and trends of

properties throughout all the elements.

23) Transportation is the single largest market for aluminum. Name several applications of

aluminum in transportation, and why it is so useful in this sector.

Aluminum is widely used for building cars, airplanes, and railroad cars. This is because

aluminum is a very malleable, ductile, corrosion resistant, and most importantly, light weight.

Aluminum’s light weight allows for more fuel efficient, and lightweight vehicles. It is also a very

strong metal, even thought it is one third as dense as steel or copper.

24) Why is the body of a car often made using steel, which rusts, but never aluminum, which

does not corrode easily?

Aluminum can conduct heat and electricity easily, which is not beneficial for the outer layer of a

car. This causes the surface to be very hot on sunny days, and possibly damaging to the interior.

As well, aluminum reflects light very easily, which can be distracting on the road. Steel is very

sturdy, and can maintain its shape for a longer period of time.

6.2 Elements on Planet Earth, p204

1) Use four physical properties to compare metals, nonmetals, and metalloids.

Type of Element State at Room Temp. Lustre Conductivity Malleability and Ductility Examples

Metals Solid

(except Mercury liquid) Shiny Lustre Good conductors of heat and electricity Malleable and

Ductile (can be hammered and stretched) Lithium

Beryllium

Gold

Silver

Nonmetals Solids and Gases

(except Bromine liquid) Dull, not Shiny Poor conductors of heat and electricity Brittle and Not

Ductile (can’t be shaped or stretched) Nitrogen

Oxygen

Radon

Hydrogen

Metalloids Solid Shiny or Dull May conduct electricity, Poor heat conductors Brittle and Not

Ductile (can’t be shaped or stretched) Boron

Silicon

Arsenic

Polonium

2) Describe the cycles for oxygen and carbon dioxide, nitrogen, and water. Be sure to indicate

how each of these substances returns to the atmosphere.

Oxygen and Carbon Dioxide – Photosynthesis from plants takes CO2 gas, light, and water to

create complex carbon compounds, and oxygen. This is how oxygen and carbon dioxide is then

released back into the atmosphere. It is then used in respiration for all of the cells of all

organisms, all the time. Photosynthesis then takes the CO2 and the process repeats.

Nitrogen – Nitrogen is present in all proteins, and is vital for life. Nitrogen then is soaked up by

the roots of plants from decomposed living organisms, and released again into the atmosphere as

N2 gas.

Water – Water in the atmosphere rises, cools, and condenses into clouds. Water droplets then

form in clouds, and precipitation occurs. H2O is then absorbed by plants, rivers, and the soil, and

makes its way to large bodies of water. Water then evaporates, and returns to the atmosphere.

3) List the chemical compounds in the hydrosphere, and write a sentence that explains the role of

each compound.

Dissolved O2 gas – Water animals such as fish depend on it to respire

Dissolved CO2 gas – Water plants such as sea weed use it to make food

NaCl, KCl, CaCl2 – These three compounds make up sea salt that came from rocks and soil that

make up the continents, causes sea water to be salty

6,3 – The Science and Technology of Metallic Elements (Worksheet)

1) Metallurgy – The science and technology of retrieving metallic elements and making them as

useful as possible

2) The three major processes of metallurgy are extraction, modification, and alloying.

Term Definition

Ore A body or deposit of rock, gravel, sand, or earth worth mining for the mineral or minerals it

contains

Mineral A natural, pure, inorganic substance with a unique chemical composition. (Ex: Silicon,

Quarts, Hematite)

Metal A chemical substance such as Gold, Aluminum, or Iron; metals share similar properties

including a metallic lustre, malleability, ductility, and a good ability to conduct heat and

electricity

Modification The process of altering the properties of a pure metal without using a chemical

change (Ex: By heating and sudden cooling)

Alloying The process of producing an alloy by mixing a metal with one or more metals or

nonmetals (Ex: Brass is produced by alloying Copper and Zinc)

Smelting The process of heating ore to obtain the metal from it

Tempering A process that increases the hardness and toughness of a metal

3)

4) Extracting Metallic Elements from Ore

Refer to page 205 Figure 6.12

5) Two metals that are extracted by smelting are Iron (from magnetite and hematite) and copper.

6) The mineral that contains aluminum is bauxite. Bauxite is mixed with Sodium Hydroxide to

concentrate the ore and make the process of electrolysis easier.

7) Alumina or Aluminum Oxide (Al2O3) contains Aluminum and Oxygen, Hematite (Fe2O3)

contains Iron and Oxygen, and Magnetite (Fe3O4) also contains Iron and Oxygen.

8) Iron is less expensive than Aluminum because the process for mining iron is much quicker and

less costly than the process for mining aluminum. The various problems of mining aluminum

make it more costly to mine.

9) Some of the minerals that Canada exports are Aluminum, Coal, Nickel, Copper, Gold, and

Uranium.

Chapter 7 Review

Models of Atomic Structure

Chapter 7 Review Worksheet

Part A

I am the device that aided in the discovery of the electron: Discharge Tube

I am the scientist that shot alpha particles at a piece of gold foil: Rutherford

I am the subatomic particle that resulted from this experiment: Neutron

I am another name for the negatively charged electrode of a power source: Cathode

I am another name for the positively charged electrode for a power source: Anode

I am the name for the 3 structures that make up an atom: Subatomic Particles

I am the property of elements such as uranium that defines the emission of radiation:

Radioactivity

I am the +ively charged particle emitted by the nucleus of some radioactive atoms: Alpha Particle

I am an electron ejected by the nucleus of some radioactive atoms: Beta Particles

I am the part of the atom with the most mass and the least volume: Nucleus

I am the part of the atom with the least mass and the most volume: Electron Cloud

I am the subatomic particle that has a positive charge: Proton

I am the subatomic particle that has a negative charge: Electron

I am the subatomic particle that has no charge and so is neutral: Neutron

I am the scientist that proved that cathode rays have mass and motion: William Crooks

I am the scientist who developed a model of the atom that resembled a billiard ball: Dalton

I am the scientist who developed a model of the atom that resembled the solar system: Bohr

I am the scientist who developed a model of the atom that resembled a raisin muffin: Thompson

I am the scientist that discovered radium: Marie Curie

I am the scientist who included the neutron in Rutherford’s model of the atom: Bohr

I am the term that refers to the number of protons in an atom: Atomic Number

I am the term that refers to the number of protons and neutrons in an atom: Atomic Mass

I am the unit used to measure that mass of an atom and my symbol is u: Atomic Mass Units

I am the smallest unit of matter that can take part in a chemical change: Atom

I am a form of element that has a different atomic mass: Isotope

I am the basis in which the present day period table is organized: Atomic Mass

Part B

Complete the following chart on the Parts of an Atom

Name Charge Mass Location

Proton Positive 1 u Nucleus

Electron Negative 1 / 1837 u Electron SHells

Neutron Neutral 1 u Nucleus

1u = 1/12 the mass of a 126Carbon Atom

Unit 2 – Atoms and Elements

Chemistry Review Questions


3) F – Alkali metals do not react with Nobel Gases

4) F – A chlorine ion has 1 more electron than a chlorine atom

5) F – Temper cases copper to become stronger and less malleable

6) F – Not all compounds with giant structure are ionic

11) The alkali metals have one less valence electron than the alkali earth metals.

12) Elements in the same group have similar properties.

13) Matching

Process involving the formation of new compounds Chemical Bonding

The rearrangement of atoms into new substances Chemical Change

A homogeneous mixture Solution

Atoms of the same element with different numbers of neutrons Isotopes

The type of ion most commonly formed when a non-metallic elements becomes an ion

Negatively Charged Ion

The number of protons and neutrons in the nucleus Mass Number

The basis for arranging elements on the periodic table Atomic Number

20) A K+ ion has the sane number of electrons as a Cl- ion.

24) What is the difference between a mineral and an ore? Why are ores usually concentrated

where they are mined?

A mineral is a natural compound containing metal, while ore is large deposits of rock, sand, or

earth which contain the mineral. The concentration of ore is to make sure that the remaining

mixture contains as much mineral as possible, to make decomposition easier, and also to remove

unused rock.

28) Why is an atom’s outermost shell of electrons important?

An atoms outer shell of electrons, or Valence Electrons, are important as they determine how the

atom reacts with other elements in chemical reactions, and also determines the physical properties

of that element.

30) Relate the electron structure of aluminum to its position in Period 3 and Group 13 of the

periodic table.

Aluminum is in group 13, therefore it has 3 valence electrons. As well, it is in period 3, therefore

it has 3 electron shells.

31) How do electron dot diagrams for Calcium and Argon compare with the electron dot

diagrams for Strontium and Krypton?

The Calcium – Strontium diagrams and the Argon – Krypton diagrams would be very similar,

with the same number of valence electrons (dots). The only difference visible in the diagram is

the name of the element itself. The differences would be the number of electron shells, and the

number of protons and neutrons, although this is not represented in an electron dot diagram.

Calcium and Strontium have two valence electrons, Argon and Krypton have a full shell of 8

valence electrons.

42) Number of Protons, Neutrons, and Electrons for:

5626Fe3+ - Positive Iron Ion, 26 Protons, 30 Neutrons, 23 Electrons

6630Zn2+ - Positive Zinc Ion, 30 Protons, 36 Neutrons, 28 Electrons

147N3- - Negative Nitrogen Ion, 7 Protons, 7 Neutrons, 10 Electrons

12050Sn4+ - Positive Tin Ion, 50 Protons, 70 Neutrons, 46 Electrons

43) How many Oxygen Ions are in:

MgO has 1 O-2 Ion, Fe2O3 has 3 O-2 Ions, and P2O3 has no O Ions. (P2O3 is a covalent bond,

so the electrons are shared and oxygen does not become an ion)

44) Write the formulas for these ionic compounds: (note that in ionic bonds, no suffixes, prefixes,

or roman numerals are needed unless there are different oxidation numbers for the elements)

Oxygen and Potassium makes Potassium Oxide (K2O)

Sodium and Sulfur makes Sodium Sulfide (Na2S)

Bromine and Magnesium makes Magnesium Bromide (MgBr2)

Aluminum and Iodine makes Aluminum Iodide (AlI3)

Beryllium and Oxygen makes Beryllium Oxide (BeO)

45) Which are possible and which are not?

FO3 is impossible, Na2O3 is impossible, HCL is possible, Ca2Cl is impossible.

46) Cesium is:

An Alkali Metal, more reactive than sodium, potassium, and rubidium, is malleable, and is a solid

at room temperature.

Review: Element Names and Symbols

Complete the Following Chart:

Element Symbol Element Symbol Element Symbol Element Symbol

Hydrogen H Sodium Na Beryllium Be Magnesium Mg

Helium He Argon Ar Neon Ne Aluminum Al

Carbon C Lithium Li Calcium Ca Sulfur S

Nitrogen N Boron B Phosphorus P Chlorine Cl

Oxygen O Potassium K Fluorine F Silicon Si

What Element am i?

Description of Element Name Symbol

I am the only gas in Group 1 Hydrogen H

I am the inert gas found in Period 3 Argon Ar

I am the element with an atomic mass of 16 Oxygen O

I am the element that you burned in the lab that gives a purple flame Potassium K

I am the element found in toothpaste to help prevent cavities Fluorine F

I am the element that combines with chlorine to make table salt Sodium Na

I am the element that has an atomic number of 4 Beryllium Be

I am the element that if you inhale me you will sound like Donald Duck Helium He

I am the element that is present in your pencils Carbon C

I am the element that is found in fertilizers that makes grass greener Nitrogen N

I am the element needed for strong bones and teeth Calcium Ca

I am the element that is used to keep swimming pools clean Chlorine Cl

I am the element that is in the 3rd Period and the 2nd Group Magnesium Mg

I am the element in the 1st Group that has two energy levels Hydrogen H

I am the most abundant element on the Earth’s crust Oxygen O

I am the element that combines with oxygen to make sand Silicon Si

I am the element that exists as a diatomic molecule and supports combustion Oxygen O

I am the element with an atomic mass of 31 Phosphorus P

I am the first element on the metallic staircase Boron B

Classify the first 20 elements into one of the following categories: (elements can fit into more

than one category.

Metals Nonmetals Metalloids Diatomic Molecules Inert Gasses

Lithium

Beryllium

Sodium

Magnesium

Aluminum

Potassium

Calcium Helium

Carbon

Nitrogen

Oxygen

Fluoride

Neon Phosphorus

Sulfur

Chlorine

Argon Boron

Silicon Hydrogen

Nitrogen

Oxygen Helium

Neon

Argon

Isotopes (Note)

- Atoms of the same element with the same atomic number but with a different atomic mass

- Same number of protons, but a different number of neutrons

- The atomic mass listed for an atom is really an average of the mass of all of its isotopes. This is

why it is a decimal

Periodic Table Families

I. Alkali Metals (Li, Na, K, Rb, Cs, Fr)

- high chemical reactivity, most reactive metals, react vigorously with water

- reactivity of metals increases as we go down a column of the periodic table

- hardness and melting point decrease as you go down

II. Alkaline Earth Metals (Be, Mg, Ca, Sr, Ba, Ra)

- reactive chemically, not as much as alkali metals

- some are non-soluble in water

- mostly found in the earth, hence Earth Metals

Transition Elements

- they back fill, and likely have more than one oxidation number

Inner Transition Elements

- the two long rows of elements below the table (Lanthanide and Actinide Series)

XVII. Halogens (F, Cl, Br, I, At)

- nonmetallic group, highly reactive

- reactivity decreases as we go down the table

- opposite trend as metallic elements

XVIII. Nobel Gases (He, Ne, Ar, Kr, Xe, Rn)

- very limited degree of chemical reactivity

- heavier elements have smaller reactivity

Compounds and Bonds

- The smallest unit of a compound is a molecule

- We often give names to compounds instead of using the full scientific name

Molecular Bonds (Covalent)

- electrons are shared so that each atom has a full octet

- often form between two nonmetals

- both atoms acquire enough valence electrons to have a full octet like the nearest noble gas

- covalent bonds form when there is not a great difference in electronegativity

- there can be single, double, or triple bonds

Eg: There are two Oxygen Atoms. Each has 6 valence electrons, thus they need two more to have

a full octet. (that means its oxidation number is -2). The result is a double bond. The oxygen

atoms share their two unpaired electrons.

Water, H2O

Carbon Dioxide, CO2

Methane, CH4

Propane, C3H8

Glucose, C6H12O6

Ammonia, NH3

Sucrose, C12H22O11

Hydrogen Peroxide, H2O2

The above are some special names given to specific covalent compounds.

We use the Prefix System when naming covalent bonds. (Only the prefix system is used for

naming covalent bonds, nothing else) The number of each element is indicated by a Prefix:

1 (Mono) 2 (Di) 3 (Tri) 4 (Tetra) 5 (Penta) 6 (Hexa) etc.

- If there is only one of the first atom, no prefix

- The second element ends with –ide.

- named from left to right on periodic table (in order of electronegativity)

(Prefix + Element), (Prefix + Element + IDE)

Eg:

P2O3 – Diphosphorus Trioxide

CO2 – Carbon Dioxide

N2O3 – Dinitrogen Trioxide

Ionic Bonds

- electrons are given or taken so that each atom becomes like its nearest noble gas

- often form between a metal and a non metal

Eg: There is one sodium atom and one chlorine atom. The sodium atom wants to lose one

electron, while the chlorine atom wants to gain one (in order for them both to have a full octet

and become like the nearest noble gas). The result is that the sodium will give it’s extra electron

to the chlorine, resulting in an ionic bond.

Sodium Chloride (Salt), NaCl

Iron Oxide (Rust), Fe2O3

Calcium Sulfide, CaS

There are three ways to naming an ionic bond.

1) For Regular Ionic Bonds with One Oxidation Number – Nothing Special

- Merely add an IDE to the end of the second element and you’re done. It doesn’t matter how

many of each there are. The metal always goes before the nonmetal.

Eg: Al2O3 – Aluminum Oxide (Aluminum wants to lose 3 electrons even though it is near the

right)

2) For Ionic Bonds involving an element with Two or More Oxidation Numbers:

i) Stock System (Roman Numerals):

A roman numeral is put after the first element to represent it’s oxidation number.

Eg: CuCl is Copper (I) Chloride, but CuCl2 is Copper (II) Chloride.

ii) Classical Method (Prefix System):

For the lower oxidation number, the suffix OUS is applied after the first element.

For the higher oxidation number, the suffix IC is applied after the first element.

The latin name for the metal is used instead of the modern name.

Eg: CuF is Cuprous Floride, but CuF2 is Cupric Floride. (Oxidation numbers of Copper are +1

and +2, and the latin name is Cuprum).

Ionic Compounds Molecular Compounds

- high melting and boiling points

- hard

- good electrical conductors in liquid state

- non-conductor in solid state

- no noticeable odour

- generally soluble in water - low melting and boiling points

- soft

- poor electrical conductors even in liquid state

- non-conductor in solid state

- volatile odour

- generally insoluble in water

Diatomic Molecules

These are molecules made of two atoms of the same element

Oxygen - O2

Hydrogen - H2

Fluorine - F2

Nitrogen - N2

Chlorine - Cl2

What parts of Dalton’s Atomic Theory are now thought to be wrong? Explain why.

- “Atoms cannot be created, destroyed, or divided”: presently, we know that there are subatomic

particles within atoms which means they can be divided (protons, neutrons, electrons). As well,

using nuclear technology, we can bombard an atom with electrons to split it

- “All atoms of the same element are identical in mass and size”: We now know that there are

such things as Isotopes, which are atoms of the same elements with different masses due to their

number of neutrons.

Trends in the Periodic Table

Metallic Properties

- Metallic Properties decrease left to right across a period

- Metallic Properties increase down a group

-

Reactivity

- Metals

o Reactivity increases down a group

o Reactivity decreases left to right across a period

- Nonmetals

o Reactivity decreases down a group

o Reactivity increases left to right across a period (excluding noble gases)

Atomic Radius

Definition: the distance from the centre of the nucleus of the atom to the outermost occupied

energy level

- Atomic Radius decreases left to right across a period

o As we go left to right, the number of positive charges in the nucleus increases (more protons),

therefore they attract the electrons more and thus decreasing the radius. As well, there is an

increase of electrons

- Atomic Radius increases down a group

o As we go down, another electron shell is added, therefore the radius is larger

Ionization Energy (IE)

Definition: the amount of energy required to remove an electron from the outermost occupied

shell of an atom

- IE increases left to right across a period

o As we go right, the Atomic Radius decreases, therefore the electrostatic forces between the

protons and electrons has increased, thus Ionization Energy increases as well because it is harder

to remove an electron

- IE decreases down a group

o As the Atomic Radius increases, the negative electrons are further from the nucleus, where the

positive protons are. Therefore there is less attraction holding the electrons in, and they can be

taken away easier.

Electron Affinity

Definition: the amount of energy that is released when an electron is gained by an atom. (As an

electron slows down, it releases more energy)

- Electron Affinity increases left to right across a period, except for noble gases which have an

Electron Affinity of 0

o Elements with the greater ability to form ionic bonds have a higher Electron Affinity. (ie.

Halogens).

- Electron affinity decreases down a group

o The further the electrons are from the nucleus, the faster the electrons are going, meaning lower

Electron Affinity. The smaller the atom receiving the electron, the greater the energy required,

therefore the higher electron affinity.

Electronegativity (EN)

Definition: a relative measure of an atom’s ability to attract shared electrons in a chemical bond

- EN increases left to right across a period

o Electrons to the right of the periodic table have a greater want to become stable by gaining

electrons, so they have a greater ability to attract electrons.

- EN decreases down a group

o Since the atom has a larger Atomic Radius, the valence shell which attracts the shared electron

is further from the nucleus and has less positive attractive forces

The difference in electronegativity between two elements when they form a chemical bond is

what determines if they form a covalent, polar covalent, or ionic bond.

- If the EN is the same for both the elements, the electrons will be shared equally which results in

a covalent bond. Notice how the non-metals have similar EN’s, as they are in the same region of

the period table. This is why they form covalent bonds.

- If the EN is almost the same for both the elements, the electrons will be shared slightly

unequally resulting in a polar covalent bond

- If there is a huge difference in EN between the two elements, the element with the higher EN

will take the electron forming an ionic bond. Notice how ionic bonds usually form between a

metal and a non metal. They are on opposite sides of the periodic table, meaning they have great

This is almost all of it, the rest is in the textbook.

Exploration of the Universe

Exam Revision Notes – Science

Ch 13 – The Changing View from Earth (p428)

Key Terms

Celestial Bodies – the collective term for the Sun Moon, stars, planets, natural satellites, and

comets

Asterism – a distinctive star pattern

Constellation – a group of stars that form a pattern

Planet – a celestial body that orbits a star and does not produce its own light

Retrograde Motion – in a celestial body’s orbit, an actual or apparent movement opposite to that

of the usual east-to-west direction

Geocentric Model – Earth-centered model of the solar system

Heliocentric Model – Sun-centered model of the solar system

Celestial Sphere – an imaginary sphere once thought to enclose the universe and in which the

plants and stars seem to be fastened

Epicycle – a small circle whose centre rolls around the circumference of a larger circle

Solar Plane – an imaginary, flat disk extending out from the Sun’s equator on all sides, along

which our solar system’s plants (except Pluto) orbit the Sun

Solar System – the family of the Sun and all the plants and other celestial bodies that revolve

around it

Solar Prominence – a large eruption of glowing gas that starts on the Sun and rises high above it

Sun Spot – a region on the Sun that is cooler and therefore looks darker than its surroundings

Solar Flare – near sun spots, a high-temperature eruption of gases on the Sun; solar flares usually

cause radio and magnetic disturbances on Earth

Solar Wind – streams of electrically charged protons and electrons discharged by the Sun, often

associated with sun spots and solar flares

Photosphere – around the Sun, the region from which the Sun’s light originates

Corona – an irregularly shaped halo around the Sun

Inner Planets – Mercury, Venus, Earth, Mars. Also known as the terrestrial planets, because of

their rocky composition

Outer Planets – Jupiter, Saturn, Uranus, Neptune. Are similar because of their gaseous

composition

Astronomical Unit (AU) – one astronomical unit is equal to the distance from the centre of Earth

to the centre of the Sun (149 599 000 km)

Asteroid – any of the millions of small planets between the orbits of Mars and Jupiter

Comet – a small celestial body that orbits the Sun and has a bright nucleus and a fainter tail,

which always point away from the Sun

Meteor – a solid body that enters Earth’s atmosphere from outer space, becoming hot and bright

because of friction with the atmosphere

Meteorite – the remnant of a meteor that does not burn up completely in Earth’s atmosphere; it

falls to Earth as a solid body made up mainly of stone or iron

Celestial Motion in the Early Days (p430)

• Sailors used the stars to navigate and guide their boats

• Farmers planted and harvested crops according to the patterns

• Political and religious leaders often made decisions based on the information received from

those who studied the sky

• People believed their destinies could be foretold by the stars

Celestial Patterns (p430-433)

Moon:

• The moon rises in the east and sets in the west

• A full moon rises exactly at sunset

• The moon rises one hour later than the night before

• The phases of the moon are always changing

Sun:

• The sun rises in the east and sets in the west

• The sun rises earlier and farther north each morning and sets later each day from late December

to late June

• From late June until late December the sun rises later and sets earlier further South

Stars, Constellations and Asterisms

• Most follow the same pattern of the Sun and Moon

• Stars reveal a seasonal pattern

• One notable star that never rises or sets is Polaris (North Star), around which all the other stars

appear to be revolving

Planets

• Mercury, Venus, Mars, Jupiter, and Saturn show patterns in the sky

• Venus and Mercury seem to stay near the Sun and while they are visible they can be seen in the

early evening or morning

• Mars, Jupiter, and Saturn have a retrograde motion which means to loop back briefly before

continuing eastward

Miscellaneous Facts

• The Earth revolves around the Sun once very 365 ¼ days, which causes the 4 seasons

• The Earth spins on its axis once every 24 hours, which causes day and night

• The moon revolves around the Earth every 28 days (a month)

Geocentric Model – Earth Centered Model (p435-436)

• Early astronomers believed that the Earth was the center of the universe

• They assumed that the Sun, Moon, and stars revolved around the stationary Earth

• The idea arose from the apparent motion of objects in the sky (rose in the east, set in the west)

• It is based on ideas of Greek philosopher Aristotle

• Hipparcus was the first to offer detailed explanation of how objects move through the solar

system

• The diagram consisted of the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn with the

Earth in the center

• “Epicycles” were small secondary orbits that accounted for the periods when planets appeared

to move backwards (retrograde motion) with respect to the Earth

Heliocentric Model – Sun Centered Model (p436)

• In 1507, astronomer Nicholas Copernicus proposed that the Sun was at the center

• He also suggested that Earth was a relatively small and unimportant component of the universe

• He was troubled by the movement of the planets, to account for their positions relative to the

Earth.

• For example, Mars, Jupiter and Saturn (not Mercury and Venus at the time) were said to move

in reverse direction from time to time

• This movement was an illusion that occurs because of the different lengths of the planet’s orbit

Rotation vs. Revolution (see notes)

• Rotation is the spinning of an object around its axis, revolution is the movement of one object

traveling around another

• One rotation of the Earth takes 24 hours, one revolution takes 365 ¼ days

• Rotation causes most stars to appear to rise in the east and set in the west, revolution allows us

to view different stars and constellations during different seasons

Retrograde Motion (see notes)

• The apparent change in the direction of travel of the planets against the background of stars over

a period of many nights

• Mars, Jupiter, and Saturn are said to move in reverse direction from time to time

• The backward motion is merely an illusion because of the different lengths of the planets’ orbits

• These 3 planets are father from the Sun, so their orbit is longer than that of the Earth

• Earth overtakes the other planets as it circles the Sun it its shorter path.

The Sun (see notes)

• Average sized, middle aged star

• Huge globe made of mostly hydrogen (¾ hydrogen, ¼ helium)

• 1.4 million km in diameter-110X the diameter of Earth

• So HOT it glows!

15000000 C (core region)

Light speeds through space

Hot enough to allow fusion

• Nuclear fusion

Joins the nuclei of atoms to produce different atoms

Atoms of hydrogen fuse to form helium

Huge amount of energy is released by this reaction

• The energy released works its way to the photosphere regions the Sun’s light originates

Regions of the Sun

• Corona – The outmost layer of the Sun that is visible during an eclipse. Its gases can reach up to

1 million C!

• Photosphere – “Sun’s” surface, temperatures can be 6000 C

• Chromosphere – inner layer of the Sun, has a pinkish colour from the light produced by

hydrogen gas

The Active Sun

* see key terms for definitions

But the sun produces...

Auroras (Aurora Borealis in the North Pole, Aurora Australanis in the South Pole)

• Visible effects

• Caused by interaction of solar wind and Earth’s magnetic field

• Plasma approaches Earth, and ions are drawn toward the north and south magnetic poles

• Plasma breaks apart O2 and N2 in Earth’s atmosphere, causing it to glow

Our Planets

Mercury

• Closest planet to the sun

• About the same size as the Moon

• Extremely hot during the day, but extremely cold during the night

• Has no real atmosphere

Venus

• 2nd planet from the Sun

• Closest in size to the Earth

• Sometimes referred to as the evening star

• Brightest planet. The brightness comes from its toxic atmosphere

• Has permanent volcanoes

• No chance for human life to exist on Venus

• Has retrograde motion

Earth

• 3rd planet from the Sun

• Only known planet with life

• Very few have seen it from space

• 4 billion years ago, it was similar to Venus

• Has large percent of oxygen in its atmosphere

• Has a moon which orbits Earth in one month. It also makes a complete

rotation on its side

Mars

• 4th planet from the Sun

• Known as the “red” planet

• Most likely place of life, many alien stories

• Many probes sent there

• Red colour comes from rust

• Only other planet for possible habitation

• Temporarily good for life

• A space probe once sent back to Earth images of dust storms from the

surface

Jupiter


• Known as a “gas giant”

• Biggest planet in our solar system

• Has 39 moons

• “Big eye” source of massive hurricane

• Has a “Great/Giant Red Spot”

• Mass is 2.5 times the mass of all the other planets combined

• Has a moon with a possible ocean of water under a crust of ice

Saturn


• Has visible rings composed of ice-covered rock fragments and dust

• Colours are yellow and white

• Rings are most visible compared to other planets

• Has a moon with an atmosphere (Titan)

• Planet could float in a tub

Uranus


• Movement caused by another body

• Featureless

• Rotates on axis on 90 degrees (rolls on its equator)

• Only planet where Sun isn’t directly over its equator

Neptune


• Blue colour comes from methane gas

• Has a big dark spot

• Named after the Roman god

• The last gas giant

• Discovered through knowledge of Newton’s law of gravitation

• Pluto’s orbit crosses inside Neptune’s orbit

Pluto


• As of 2007, it is no longer a planet

• Cold because it’s the farthest from the Sun

• Smallest “planet”

• Neither an inner planet or a gas giant (outer planet)

• Has elliptical orbit and retrograde rotation

Our Solar System (p445)

Galileo’s Support for the Copernican Heliocentric Model (p437)

• Galileo found persuasive evidence that supported the model

• Technology was a big part

• Using an early telescope, he made several discoveries

• Venus exhibited phases just as the Moon did

• He also saw spots on the surface of the Sun, mountains on the Moon’s surface, rings around

Saturn, and four moons orbiting Jupiter

Planisphere, Astrolabe, And How to Use Them (see notes)

• A planisphere is a polar projection of half or more of the celestial sphere on a chart equipped

with an adjustable overlay to show the stars visible at a particular time and place.

• It is used by rotating the discs to your desired date and time and the stars that you should see at

that time will look the same in the night sky

• An astrolabe is a medieval instrument, now replaced by the sextant, which was once used to

determine the altitude of the sun or other celestial.

• It is used by aligning the special attachment with the “straw” and pointing at an object, and then

putting down the protractor part until the base is parallel with the ground. Whatever angle your

attachment is pointing at is the altitude of the object

Asteroids, Comets, Meteorites, and Meteors (p454)

• Asteroids

Small relatively small chunks matter (“minor planets”)

Shine like dots of light but orbit the Sun

Made of carbon-rich rock; iron or nickel; other elements

Irregular in shape and size-vary in size from 1000 km to less than 1 km

Located in belts that lie between the orbits of Mars and Jupiter

5000 asteroids have been tracked and documented but we believe that millions exist

• Meteors & Meteorites

Meteors (“shooting stars”) are small particles of dust left behind by a comet’s tail

Appear as sparks that vaporize and fizzle in the sky

Meteor showers occur when the earth passes through the orbit of a comet or debris left by a

comet; January 1-4, April 19-23, August 12-14, October 18-23, November 14-20, and December

10-15

Meteorites are larger chunks of rock, metal, or both that break off an asteroid or comet and

crash down onto Earth-vary in size (ex. 2000 years ago, meteorite landed in Arizona creating a

crater 1.2 km wide and 174 m deep

• Comets

“dirty snowballs”; clumps of rocky material dust and frozen methane, ammonia and water

Starlike consisting of a nucleus, a head and a gaseous tail

Tail (always point away from the Sun) formed when the comet melts as it nears the Sun

Orbit the Sun in elliptical paths

Trillions of inactive comets lie on the outskirts of the solar system (one light year from earth) in

an Oort cloud until a passing gas cloud or star jolts a comet into orbit

Hailey’s comet (next pass in 2062)

Phases of the Moon (see notes)

• Waxing – the lunar phase when the moon is getting “larger” (nearing the full moon)

• Waning – the lunar phase when the moon is getting “smaller” (more crescent-like)

• Gibbous – A shape similar to the Moon when it is more than half lit but less than a full

• Crescent – Any shape resembling the curved shape of the moon in its first or last quarters

• The moon’s phases take up 29.5 days

• During the first 15 days of the cycle, the new moon turns into a full moon, and in the second 15

days of the cycle the full moon turns back into new moon

• 2-7 days after the new moon – waxing crescent

• 8th day after the new moon – first quarter

• 9-15 days after the new moon – waxing gibbous

• 16th day after the new moon – full

• 17-22 days after the new moon – waning gibbous

• 23rd day after the new moon – third quarter

• 24-29 days after the new moon – waning crescent

• 29.5-30th day after the new moon – new

Ch 14 – The Lives of Stars (p460)

Key Terms

Electromagnetic Spectrum – the arrangement by wavelength of the different forms of

electromagnetic radiation

Luminosity – a measure of the total amount of energy a star radiates per second

Binary Stars – two single stars orbiting one another

Solar Mass – the basis of comparison for measuring star mass; the Sun has a solar mass of one

Red Dwarf – a small, cool star that is not very bright

Main Sequence – on the Hertsprung-Russell diagram, a narrow band of stars into which fall most

stars including our Sun

White Dwarf – a small, hot star that is not very bright

Red Giant – a large, bright star that is not very hot

Supergiant – an extremely large red giant (star)

Nebula – a vast cloud of gas and dust, which may be the birth place of a star (plural: nebulae)

Fusion - the transformation of hydrogen into helium. Occurs in the core of stars and involves the

creation of new elements because nuclei combine

Planetary Nebula – a fuzzy object that is not a planet but that, through a telescope, resembles a

planet such as Neptune

Black Dwarf – the final phase of a white dwarf (star)

Supernova – a huge explosion constituting the death of a star

Neutron Star – a small super-dense star thought to be the crushed remnant of a large star that has

exploded as a supernova

Black Hole – in space, an object having such strong gravity that nothing, not even light, can

escape it

Inter-stellar Medium – the space between the stars and the material it contains

Solar Nebula Theory – the hypothesis that many astronomers currently hold about how our solar

system developed

Extra-solar Planet – a planet that orbits a star other than the Sun

The Electromagnetic Spectrum (p462)

• Is the arrangement of electromagnetic radiation

• Human eye can only perceive a tiny portion that hits Earth

• Visible light is the light that human eye can detect

• Visible light is a form of energy transmitted by electromagnetic waves

(read from right to left for order from longest-shortest wavelength)

Properties of Stars (p462)

• There are 11 properties of stars that astronomers can measure: Distance, Luminosity,

Brightness, Colour, Temperature, Composition, Rotation, Direct & Speed of Motion,

Circumstellar Matter, Diameter, and Mass

The Brightness of Stars (p463)

• Luminosity is a measure of the total amount of energy a star radiates per second

• Surface temperature and mass are two factors that affect the luminosity of stars

• To compare luminosity of stars we use our Sun as the reference because it is the closest

• The range for luminosity is 10,000<Sun – 30,000>Sun

The Temperature and Composition of Stars (p463)

• Scientists use the colour of stars to infer its surface temperature

• Star colour also tells us about a star’s composition

• The instrument used to study colour is a spectroscope, which separates light into a spectrum

• Spectral patterns, star colour and temperature can be used to classify stars

Colour Blue Bluish

White White Yellowish

White Yellow Orange Red

Temperature °C (1000) 25-50 11-25 7.5-11 6-7.5 5-6 3.5-5 2-3.5

Examples Zeta

Orionis Rigel

Spica Vega

Sirius Polaris Sun

Alpha Arcturus Befelgeuse

The Size and Mass of Stars (p466)

• When scientists know the luminosity of a star they can calculate the size/radius

• Luminosity can be measured with an instrument much like the photometer (“distance meter”)

• The range of star sizes is from 0.10 of the radius of the Sun to 1000x the Sun’s radius

• A binary star is two single stars orbiting one another

• Astronomers determine the mass of each binary star by knowing the size of the orbit of a binary

pair, and the time the two stars take to complete one orbit

• Star mass is expressed in terms of solar mass (Sun=1) with a range of 0.08 solar mass to over

100 solar masses

The Hertzsprung-Russell Diagram (p466-467)

• From the HR diagram, astronomers discovered that there are several different types of stars

• The diagram shows that there is a relationship among star colour, temperature, luminosity, and

mass

• 90% of stars are located in the main sequence

• A cooler star might appear to be brighter than a hotter star because it could be closer to the

observer, or larger in diameter

The Evolution of Stars: The Star Cycle (p468-473)

Stage 1: NEBULA

• The birthplace of stars is known as a nebula

• The raw materials of stars are interstellar gas and dust

Stage 2: MAIN SEQUENCE STAR

• The star turns “on” when nuclear fusion begins to transform hydrogen gas into helium at a

temperature of about 10,000,000 °C

• The time that the star remains in this stable state depends on its initial mass

• The fate of this star after this point is different depending on its initial mass and the rate that it

consumes its hydrogen fuel

Stage 3a: LOW MASS STAR

• Very low mass stars, called red dwarfs, consume their hydrogen slowly and essentially

evaporate, eventually forming a very faint dwarf

• The white dwarf eventually enters a final stage where it is nothing more than a dark cinder

called a black dwarf

Stage 3b: INTERMEDIATE MASS STAR

• During this stage, hydrogen is used up in the core and helium begins to become involved in

nuclear fusion to form carbon

• The core of the star collapses and the outer layers expand. The star is now called a red giant

• As the star expands the stellar wind peels away most of the outer gases revealing the hot inner

region of the star; this star is now called a planetary nebula

• Over time, the planetary nebula disperses into space; its remains cool and become a white dwarf

• The white dwarf eventually becomes a black dwarf

Stage 3c: MASSIVE STARS

• High mass stars consume their hydrogen very quickly and their cores get so hot that helium can

fuse into heavier elements

• The star swells to form a supergiant and when the core collapses a massive amount of energy

bursts from the star’s surface causing a huge explosion called a supernova

• After going super nova, the star has four possible fates

If the remaining core is less than one solar mass the star may become a white dwarf

If the remaining core is between one and three solar masses the core may have enough gravity

to become a very dense neutron star (1967-astronomers used radio telescopes to detect radio

pulses from rapidly rotating objects called pulsars, turned out to be neutrons stars whose

existence had been predicted)

If the remaining core is larger than 3 solar masses, the gravity may be strong enough to produce

a black hole, an object so compact and dense that even light may not escape. Alternatively, the

core may be completely destroyed and a new nebula may be formed

Solar Nebula Theory (p478-479)

• Interstellar medium-space is not empty but filled with huge quantities of gas/dust, composed

mainly of hydrogen, helium, and other trace elements

Formation Of Solar System

• Formed by a solar nebula

During Formation

• 1. Gravitational forces between materials triggered shockwaves causing the nebula to collapse

in on itself {Nebula starts contracting}

• 2. Nebula contracted, spun, leading to frequent collisions of material {Nebula begins to spin

faster}

• 3. Grains stuck together to form larger objects-pebbles/rocks/boulders {Nebula flattens}

• 4. Eventually gave way to early stage of planets (protoplanets/planetesimals) {Hydrogen fusion

starts}

• 5. Nebula condenses so core temperature rises-star is formed {Centre reaches 10,000,000 °C}

• 6. Bodies father away from core become planets {Radiation from the sun blasts the rest of the

gas and dust out of the inner solar system}

• Inner planets-blasted by radiation from the Sun and not much gravity to hold hot atmosphere,

therefore it became rocky

• Outer planets-farther from intense heat and were able to keep their gas

• It is believed that: 1) Sun is 5 billion years old. 2) Our planets are 4.6 billion years old. the proof

is the geological evidence of rocks’ age

• A theory predicts that planets are common byproducts of star formation: 1) Infrared, radio, and

optical telescopes have recorded 100+ examples of young stars embedded in disks of dust and

gas. 2) They detected a dozen extra-solar planets (planets that orbit other stars)

Seasonal Calendars: The Earth’s Orbit around the Sun (see notes)

Reasons

• Earth’s axis not perpendicular to the sun’s direction but pointed to Polaris

• Sun’s rays hitting the Earth’s surface changes

• Differences in the angles of the Sun’s rays cause regular changes in average temperature know

as the season

Summer Solstice

• June 21, North Pole leans toward the Sun

• Rays shine from a high angle and light up more than half of the northern hemisphere

• Temperature is moderate, days are long and nights are short

Winter Solstice

• December 22, North Pole leans away from the Sun

• Rays shine from a low angle and light up less than half of the northern hemisphere

• Sun is low, temperatures are low, days are short and nights are long

Equinox

• March 22 and September 23

• Rays shine on exactly half of the northern hemisphere

• Daylight and darkness are equal hours

• Temperatures lie between those of summer and winter

Ch 15 – Exploring The Cosmos (p486)

Key Terms

Triangulation – a method of indirectly measuring distance by creating an imaginary triangle

between an observer and an object whose distance is to be estimated

Parallax – the apparent shift in position of a nearby object against a distant background when it is

viewed from two different points

Light-year – the distance that a beam of light travels in a vacuum in one year; about 63,240 Aus,

or 9.46 trillion km

Cepheid variable – a star that pulses, changing its brightness in a regular cycle

Milky Way – the galaxy that includes our Sun and Earth; appears as a hazy white band in the

night sky. It contains 4 billions stars, and is invisible because our solar system is on its edge

Galaxy – a huge accumulation of stars, gas, and dust held together by gravity

Open Cluster – a collection of 50 to 1,000 stars that appear dispersed along the main band of the

Milky Way

Globular Cluster – a collection of 100,000 to a million stars arranged in a distinctive spherical

shape and not appearing along the band of the Milky Way

Doppler Effect – the apparent change in frequency of sound, light, and other waves due to relative

motion between, the observer and the wave source

Red-shifted – a shifting of light from an object toward the red (longer wavelength) end of the

spectrum as the object moves away from Earth

Hubble’s Law – a law stating that galaxies are moving apart at rates that increase in direct

proportion to the distance between them

Big Band Theory – scientific explanation for the origin of the universe; according to this theory,

the universe and everything in it began in an instantaneous event that occurred between 15 and 20

million years ago

Quasar – a celestial object that looks like a star but emits much more energy; quasars are thought

to be the explosively erupting cores of colliding galaxies. They are believed to be very distant at

the edges of observable galaxies

Gamma ray burst – a powerful pulse of gamma rays that can come from anywhere in the sky,

lasts 100-120 seconds. Two hypothesis about what causes them are: 1) Two giant stars collide,

and form a black hole. 2) A star collapses

Neutrino – an elementary particle that carries no electric charge. Studied by many scientist

because it is believed that they may hold the secret of the universe’s missing mass

The Discovery of the Galaxies (p495-502)

• Solar System – the family of the Sun and all the planets and other celestial bodies that revolve

around it

• Galaxy: *see chapter key terms

• Milky Way: *see chapter key terms

• The discovery of distant galaxies tell us that the universe is much larger and more populated

with stars than we had ever expected and that our solar system is very small

Star Clusters

Type # of Stars Location Example

Open clusters 50-1,000 Along the main band of the Milky Way Pleiades

Globular clusters 100,000-1,000,000 Southern regions of the sky Hercules

• The diameter of the Milky Way is 75,000 light-years

• The Sun is located in the outer edge of the Milky Way (25,000 light-years away from centre)

• Scientists use infrared telescopes to help see through the inter-stellar material

• The Milky Way galaxy is an immense disk shape with a halo of globular clusters surrounding its

centre

• In 1925, Edward Hubble discovered Andromeda, nearest galaxy to Milky Way. This discovery

lead scientists to the realization that the universe is far larger than we ever imagined

Galaxies

Type Shape Composition Example

Elliptical Shape similar to football Old dust with very little inter-stellar gas/dust. -Most common

M32

Spiral Flat pinwheels with arms spiraling out from centre Lots of dust and gas with young blue

stars

-Lots of star formation Milky Way, Andromeda

Irregular No particular shape, smaller than above two Mix of young and old stars embedded in

gas and dust Large/Small Magellanic Cloud

• Galaxies slowly rotate, their stars circulating the galaxy centre. The Sun takes 200 million years

to complete one revolution

• The name given to the cluster of galaxies to which the Milky Way and Andromeda belong is

The Local Group

The Expanding Universe (p503-506)

• Doppler Effect: *see chapter key terms

• Policemen use the Doppler Effect to catch speeders. The radar gun sends a radio signal of

known wavelength. The returning wavelength has a different wavelength if the car is moving.

The size of the change in wavelength shows how fast the car is moving

• The Doppler Effect can be used to measure the speed and direction of light-emitting objects

such as stars

• Light waves from moving objects differ in colour. If a star’s approaching the observer, spectral

lines are blue-shifted

• If a star’s going away from the observer, spectral lines will be red-shifted

• Hubble’s Law: *see chapter key terms

• The “raisin bread model” is a model that shows how our universe is expanding. The bread

dough represents the universe and raisins represent the galaxies. As the dough rises (the universe

expanding), the distance between each raisin (galaxy) increases. This demonstrates that galaxies

do not move freely through space. Rather, space is expanding, taking the galaxies with it

The BIG BANG Theory (p507-512)

How It Happened

• 1. The universe consists entirely of light energy

• 2. Quarks and leptons (particles that make up electrons) form

• 3. Quarks combine to form neutral atoms

• 4. Protons and neutrons form helium nuclei

• 5. Helium stops forming

• 6. Electrons combine with nuclei to form neutral atoms

• 7. Galaxies form

• According to the Big Band Theory, the universe began between 15-20 billion years ago

Evidence That Reinforces the Big Bang Theory

• Penzias and Wilson’s discovery of microwave background radiation provided evidence because

they detected background static in the sky, and they were unsuccessful to their efforts to silence

it. They concluded that they picked up faint remnants of the radiation given off by the original

Big Bang event

• In the 30s, Georges Lemaître used Hubble’s Law to conclude that the universe must therefore

have started out very small and dense

Ch 16 – Earth and Space 9 (p516)

Key Terms

Greenhouse Effect – a natural process in the atmosphere that traps some of the Sun’s heat near

the Earth’s surface

Global Warming – an increase in worldwide temperatures attributed to the trapping of heat in the

atmosphere by greenhouse gases

Ozone (O3) – a form of oxygen that absorbs much of the Sun’s ultraviolet light

Magnetosphere – the space surrounding a celestial body, such as the Earth, in which that body’s

magnetic field exists

Aurora Borealis – shifting patterns of coloured light that appear in the night sky in northern

latitudes; caused by collision between charged particles and molecules in the upper atmosphere

Aurora Australanis – the same as aurora borealis but in southern latitudes

Geomagnetic storm – a cascade of particles sent into space during solar flares and drawn towards

Earth by its magnetic field

Satellite – a small body that orbits a larger one; it may be a natural satellite such as the Earth’s

Moon, or an artificial satellite sent into orbit for communications or research

Geosynchronous satellite – a satellite orbiting in synchrony with Earth’s rotation so it remains

above the same spot on Earth’s equator

Global Positioning System (GPS) – a network of artificial satellites revolving around Earth,

sending out continuous location and time signals

Extra-terrestrial life – life other than that on Earth

SETI (Search for Extra-Terrestrial Life) – collective term for a group of programs under way to

search the universe for radio signals from intelligent life

Microgravity – the condition in which objects in orbit seem to be weightless; in fact, gravity is

acting on them, but its effects are greatly reduced

The Effect of Celestial Bodies on Earth (p518-526)

Celestial Body Effect on Earth

Sun -Its heat gives warmth

-Helps for photosynthesis

-Helps all water exist

-UV light affects all organisms

-Solar wind affects communications

Moon -predict high and low tides (gravity on oceans)

Planets and Distant Stars -Astrology

-Believed to influence human affairs

-Believed to reveal character and destiny

Space Debris -Meteorites (craters

-Ice Age

-Shooting Stars

• Greenhouse effect: *see chapter key terms

• The connection between the greenhouse effect and global warming is that global warming

occurs because of the greenhouse effect. Although it is a natural process, human activities

accelerate this process too fast, which is the reason of global warming

• The ozone is an important part of the Earth’s atmosphere because it protects us from most of the

UV rays emitted by the Sun

The Use of Space (p527-535)

The Different Ways Satellites Are Used

• Communication

• Mapping

• GPS (works by triangulation after user sends signal to determine exact location)

• Space Photography

• Space Travel

• Millitary

• Navigation

• Exploring

The Satellites Used Today

• Geosynchronous satellites

• LANDSAT-used for land use interpretation and planning

• RADARSAT-transmits and receives signals through darkness and clouds using a powerful

microwave Synthetic Aperture Radar (SAR)

• NAVSTAR-used for navigation satellite tracking and ranging

The International Space Station

• A joint project from the US, Europe, Canada, Russia, and Japan

• The purpose of it is using it for long-term experiments, spacecraft construction and launching.

The ISS started in 1999

Space Careers (p541-544)

• Astronaut: The ultimate space-related career, involves being a scientist and requires good

physical condition to perform demanding tasks in small quarters of a spacecraft

• Satellite technologist: involves construction of the satellites and the development of software to

manage the satellites and interpret the data

• Aerospace industry careers: involves designing and building the spacecraft that explore the solar

system and the rockets that lift them off the earth

• Astronomer: involves teaching the subject and to carry out research

• Careers in microgravity research: involves researching microgravity and understanding its long-

term effects on the human body, as well as the spacecraft itself

Various Moons in out Solar System (see notes)

• Neptune’s Moon is Triton. The temperature is -400 °F. If you’re not wearing a spacesuit on

Triton, your head will explode within 3 seconds and your body will freeze

• Io is one of Jupiter’s many moons. Io is the hottest moon in our solar system. It also has the

largest volcano is our system. Risks involved when visiting Io are radiation showers, and poison

gas. Your best bet would be to stay underground.

• On the moon of Saturn, you could do snowboarding and jet skiing

• On the moon of Jupiter, you could do scuba diving

• Features that make Phobo (Mars’ moon) easier and safer to travel to than Mars are that it’s

cheaper, safer, easier, and it has lower gravity. We would move on Phobo by floating, because

there is very low gravity and deep dust

• The theory for the formation of our moon is that an object the size of Mars hit Earth, and the

remaining debris made the moon

• Saturn’s rings are thought to be a “moo

Documents

Chemistry Grade 9 Notes