Subatomic particles

ElectronProton

Neutron

Name

Symbol

Charge

Relative mass

Actual mass (g)

e-

p+n0

-1+10

1/1840

1

1

9.11 x 10-

28

1.67 x 10-

241.67 x 10-

24

Counting the Pieces Atomic Number = number of

protons in the nucleus # of protons determines kind

of atom The same as the number of

electrons in the neutral atom. Mass Number = the number of

protons + neutrons. These account for most of

mass

Counting the Pieces

Protons: equal to atomic number

Neutrons: Mass Number – Atomic Number

Electrons: In a neutral atom equal to atomic number

Symbols

Contain the symbol of the element, the mass number and the atomic number.

Symbols Contain the symbol of the

element, the mass number and the atomic number.

X Massnumber

Atomicnumber

Symbols Find the

number of protons

number of neutrons

number of electrons

Atomic number Mass Number

F19 9

SymbolsSymbols Find the Find the

–number of protonsnumber of protons

–number of neutronsnumber of neutrons

–number of electronsnumber of electrons

–Atomic numberAtomic number

–Mass NumberMass Number

Br80 35

SymbolsSymbols if an element has an atomic if an element has an atomic

number of 34 and a mass number number of 34 and a mass number of 78 what is the of 78 what is the

–number of protonsnumber of protons

–number of neutronsnumber of neutrons

–number of electronsnumber of electrons

–Complete symbolComplete symbol

SymbolsSymbols if an element has 91 protons and if an element has 91 protons and

140 neutrons what is the 140 neutrons what is the

–Atomic numberAtomic number

–Mass numberMass number

–number of electronsnumber of electrons

–Complete symbolComplete symbol

What if Atoms Aren’t Neutral Ions: charged atoms resulting

from the loss or gain of electrons

What if Atoms Aren’t Neutral Anion: negatively charged ion;

result from gaining electrons Take the number of electrons in a

neutral atom and add the absolute value of the charge

81

35

Br1- Identify:

Number of ProtonsNumber of NeutronsNumber of Electrons

What if Atoms Aren’t Neutral Cation: positively charged ion;

result from the loss of electrons Take the number of electrons in a

neutral atom and subtract the value of the charge

27

13 Al 3+

Identify:Number of ProtonsNumber of NeutronsNumber of Electrons

Isotopes

Atoms of the same element can have different numbers of neutrons

Different mass numbers Called isotopes

Naming Isotopes

We can also put the mass number after the name of the element.

carbon- 12 carbon -14 uranium-235

Atomic Mass How heavy is an atom of oxygen?

There are different kinds of oxygen atoms

We are more concerned with average atomic mass

Average atomic mass is based on abundance of each element in nature.

We don’t use grams because the numbers would be too small

Measuring Atomic Mass

Unit is the Atomic Mass Unit (amu)

It is one twelfth the mass of a carbon-12 atom

Each isotope has its own atomic mass, thus we determine the average from percent abundance

Atomic Mass

Is not a whole number because it is an average.

are the decimal numbers on the periodic table.

Modern Periodic Table

The modern periodic table consists of Rows and Columns

Rows - Horizontal Also known as Periods Numbered 1-7

Columns - Vertical Also known as Groups and Families Numbered 1-18

Metals

The most common class of elements is Metals

Metals become cations What is a cation? How are they formed?

Positively charged atom - Lose electrons

Metals are generally solid (except Hg), conductive of heat and electricity, malleable, ductile, and shiny

Alkali Metals

Group 1 elements are known as Alkali Metals

Alkali metals include Li, Na, K, Rb, Cs, Fr

Alkali metals are generally dull, soft, and reactive – rarely found as free elements

Alkaline Earth Metals

Group 2 elements are known as Alkaline Earth Metals

Alkaline earth metals include Be, Mg, Ca, Sr, Ba, and Ra

Alkaline earth metals are harder, denser, and stronger than alkali metals

Less reactive than alkali metals, but still rarely found as free elements

Transition Metals

Elements in groups 3-12 (3B-2B) are known as Transition Metals

Transition metals include Mn, Fe, Ag, Au, Mo, etc.

Lanthanide and Actinide Series elements fill in the f orbitals – known as inner transition elements

Metalloids

Elements that border the staircase on the periodic table are known as Metalloids

Metalloids include: B, Si, Ge, As, Sb, Te, Po, At

Metalloids have properties of both metals and nonmetals

Nonmetals

Nonmetals are found to the right of the staircase on the periodic table

Nonmetals generally become anions What is an Anion? How are they formed?

Negatively charged atom - Gain electrons

Nonmetals are often gases or dull, brittle solids

Nonmetals generally show poor conductivity, ductility, and malleability

Halogens

Group 17 elements are known as Halogens

Halogens include F, Cl, Br, and I

Halogens are the most reactive nonmetals – often found in compounds

Noble Gases

Elements in group 18 are known as Noble Gases

Noble Gases include He, Ne, Ar, Kr, Xe, Rn

Noble gases are extremely unreactive

Legend

C lass ifica tion o f M a tte r

E lem ents C om pounds

Pure Substances

H om ogeneous(SO LU TIO N S)

C o llo ids S uspens ions

H eterogeneous

Mixtures

Matter

Pure Substances Cannot be physically

separated Every sample has the same

characteristics and they can be used to identify a substance

Elements Are made up of ONE type of atom

Atoms are the smallest unit of an element that maintains the chemical identity of that element

They can be found on the Periodic Table

Examples: Carbon, Nitrogen, Calcium

Compounds

Can be broken down into simple stable substances

Are made up of two or more types of atoms that are chemically bonded

Examples: Water (H2O), sugar (C12H22O11)

Mixtures

A blend of two or more kinds of matter, each which retains its own identity and properties

Homogeneous Mixtures Have uniform

composition Also known as

SOLUTIONS

Examples: salt water, tea

Solutions ALLOYS are solid solutions that

contain at least 1 metal They are blended together so that

they have more desirable properties Some alloys you may know are:

Stainless Steel: iron, chromium, and zinc Brass: zinc and copper Bronze: tin and copper Sterling Silver: copper and silver

Heterogeneous Mixtures

Do not have uniform composition You can see the particles in them

Examples: Sand on the beach (contains sand,

shells, rocks, bugs, etc) Soil (contains dirt, rocks, worms, etc) Chicken Soup (contains water, chicken,

veggies etc)

Suspensions A heterogeneous mixture where the

solid particles eventually settle out of solution

Examples: Muddy water Mixtures of two solids Paint

Properties of Matter

All pure substances have characteristic properties

Properties are used to distinguish between substances

Properties are also used to separate substances

Physical Properties

A Physical Property is a characteristic that can be observed or measured without changing the composition of the substance

Physical properties describe the substance itself

Examples Physical State Color Mass, shape, length Magnetic properties

Chemical Properties A Chemical Property

indicates how a substance will react with another

Chemical properties cannot be determined without changing the identity of the substance

Examples: Iron Rusting Silver Tarnishing

Physical Changes

A Physical Change is a change in a substance that does not alter the substance’s identity Examples:

Grinding Cutting Melting Boiling

Chemical Changes A change in which one or more

substances are converted into different substances is called a Chemical Change

Signs of a Chemical Change: Color Change Gas is Released Temperature Change Precipitate – Solid falls out of solution Substance Disappears

Electrons

Electrons fill in an atom in energy levels

Electrons occupy the LOWEST available energy level

Energy Levels hold limited amounts of electrons 1st Level – 2 electrons 2nd Level – 8 electrons 3rd Level – 18 electrons 4th Level – 32 electrons

Chlorine (Cl)

P = 17N = 18E = 17

Nitrogen (N)

P = 7N = 7E = 7

Aluminum (Al)

P = 13N = 14E = 13

Valence Electrons

Electrons in outermost shell that determine chemical behavior

Maximum of 8 valence electrons Atoms with same valence electrons

will act similarly Group 1 elements?

1 valence electron Group 17 elements?

7 valence electrons

How Atoms Combine

Two or more atoms that are chemically combined make up a compound

The combination results in a chemical bond, a force which holds elements together in a compound

Covalent Bonds

Covalent Bonds are formed when atoms in a compound share electrons

Molecule – two or more atoms held together by a covalent bond

Usually occurs between nonmetals

Covalent Bonding in Water

Ions

An atom that has gained or lost an electron is called an ion.

Multiple atoms can combine to form an ion – called a Polyatomic Ion

Silicate (SiO44-) and Carbonate (CO3

2-) are important in forming materials at Earth’s Surface

Ionic Bonding

Positive and negative ions attract each other

Ionic Bonds occur when oppositely charged ions form a compound

Usually consist of 1 metal and 1 nonmetal

Positive ion written first in chemical formula (NaCl)

Ionic compounds have a neutral charge

Ionic Bonding in NaCl

Metallic Bonds

Metals share valence electrons between all atoms

Like a group of positive ions in a sea of electrons

Acids and Bases

An Acid is a substance that produces Hydrogen Ions in water (H+)

Acids: Sting to the touch Taste Sour React with metals

Acids and Bases

A Base is a substance that produces hydroxide ions (OH-) in water

Bases Are slippery to

the touch Taste Bitter Do not react with

metals

pH Scale

Measures the amount of hydrogen ions in a solution 0 - 6 Acidic 7 = Neutral 8 - 14 Basic

Indicators• Indicators are substances

that turn colors at different pH levels

• Examples:• Litmus• Phenolphthalein

• Base indicator• Universal Indicator: • ACID NEUTRAL BASE• Cabbage Juice• ACID NEUTRAL BASE