Chemistry Review

All Matter in the universe is

composed of…

ATOMShttps://www.youtube.com/watch?v=joOYgeqMJwU

ATOMS

Elements are composed of only one type of atom

Contain a nucleus which contain protons and neutrons

The force that hold two atoms together is a chemical bond.

Two or more atoms that are bonded together form a molecule.

Some are made up of only one type of atom but most are made up of two or more different types of atoms bonded together.

Electrons

Negatively charged

Orbit around the center of the atoms in orbits/shells called an electronic cloud

The farther from the center, the _______ energy it has

Gain and lose energy by moving between energy levels

In the nucleus of an atomPROTONS:

Positively charged and have a mass of 1The number of protons in an atoms nucleus determines what element it isThe amount of positive charge on a proton is equal to the amount of negative charge on an electron

NEUTRONS:Have no chargeMass of 1

Particle Name Location Charge Mass

Electron Orbitals -1 ~0Proton Nucleus +1 1

Neutron Nucleus No Charge 1

Atomic Number

Every atom of the same element has the same number of protons

It is the number of protons an element has which determines what element it is.

Mass Number = the total mass of an atom

It is the same as the number of protons & neutrons of the element.

One can calculate the number of neutrons an atom has by subtracting the atomic number (# protons) from the mass number.

Mass number CAN change without changing the identity of the element

Isotopes

Not all atoms of the same element have the same number of neutrons

Atoms of the same element that have different number of neutrons are called isotopes

Finding #’s

Number of Protons = Atomic Number

Number of Electrons = Number of Protons = Atomic Number

Number of Neutrons = Mass Number - Atomic Number

Periodic Table Notation:

Chemical elements are represented on the periodic table using the following format.

The letter is an abbreviation of Element NameAtomic Number Mass number.

Structure

Vertical columns are called groups or families

Numbered 1-18

Elements in each group have similar properties

Different elements with the same number of electrons in their outer energy level have similar chemical properties

Use a dot diagram to represent electrons in the outer energy level

Dot Diagram

Groups#17 “Halogens”

Group #18 “Noble Gases”

StructureHorizontal rows are called periods

Look at the step lineAll elements to the left except hydrogen are metals

The elements to the right of the line are classified as nonmentals

Elements right next to the line are metalloids because they have properties of both metals and non mentals

http://ritter.tea.state.tx.us/student.assessment/resources/online/2009/taks_g11_science/images/chart2.gif

Interactions of matter: Atoms interact through the process of chemical bonding.

Process is determined by the number of electrons found in the outermost energy level of an atom.Involves the transfer & sharing of electrons between atoms.

Matter has a variety of characteristics or properties that can differ.

They fall into 2 different groups used to identify, describe and classify matter:

1. Physical

2. Chemical

A single kind of matter that has distinct physical and chemical properties is called a substance.

A physical property can be observed without changing the substance into something else.

Odor

Taste

Hardness

Texture

Color

Temperature at which a solid melts or liquid boils

Whether its solid, liquid or gas

Physical Properties

A compound is a substance made of two or more elements chemically combined in a set ratio or proportion.

Examples: Carbon Dioxide gas is a compound made up of Carbon and Oxygen. Water is a compound made up of oxygen and hydrogen.

When elements are combined to make a compound, the new substance has properties different from those of the original elements.

Example: table sugar is made up of 3 elements- Carbon, Oxygen and Hydrogen.

Carbon=found in charcoal

Oxygen/hydrogen=colorless gases

Do sugar crystals resemble them?

Most matter occurs in mixtures.

A mixture is made from two or more substances (elements or compounds) that are in the same place but are NOT chemically combined.

Mixtures differ from compounds in 2 ways:

1. The substances in a mixture keep their individual properties.

2. The parts of a mixture are not necessarily present in set ratios.

Example: soil has particles of sand, tiny bits of clay, and pieces of decaying plants.

If you were to grab 2 handfuls of soil would they be made up of the same amount of clay, sand, and decaying plant matter?

Which is a mixture and which is a compound?

Chex mix

Table salt

Water

Muddy water

Carbon dioxide

Checkpoint

A chemical property is observed when a substance interacts with another substance.

Burning or flammability

Rusting

Tarnishing

Whether an object will explode

Chemical Properties

Elements and their Properties

Two major groups of elements

Found on the periodic tableMetals are located to the left of the zigzag line

Nonmetals are located to the right of the zigzag line

Physical Properties of

MetalsHave Luster -shiny

Are Conductors -heat and electricity move through them easily

Malleable – Can be hammered into a different shape

Ductile – Can be drawn into a wire

High Density – Heavy for their size

Metals are solid, except for mercury

Alkali Metals

Group 1 on the periodic table

Shiny, malleable and ductile

Good conductors of heat and electricity

Highly reactive metals

Transition Elements

Groups 3 – 12

Less active than groups 1 and 2

Physical Properties of NonMetals

Dull – not shiny

Nonconductors – heat and electricity do not move through easily

Brittle – break easily

Most nonmetals are gases at room temperature

Metalloids

Both metal and non metal

May conduct electricity better than many nonmetals but not as well as some metals

SolutionsTwo (or more) substances mixed so thoroughly that neither can be observed in its original form.

Homogenous mixture, in which the particles of the mixing substances are evenly distributed throughout

1) Salt water 2) Syrup (sugar in water) 3) Vinegar (acetic acid in water)4) Shampoo (various soaps and surfactants dissolved in water)

5) Oxygen

6) Brass

Solute vs Solvent

The substance being dissolved is the solute

The substance that dissolves the solute is the solvent

3 Types of Solutions

Gaseous

Liquid

Solid

How Do you Increase Rate of

Dissolving?For most solids

Increase temperatureStirShakeBreak solute into smaller pieces

SolubilityDifferent solutes dissolve at different temperatures

Solubility: the maximum number of grams of the substance that will dissolve in 100g of solvent at a certain temperature

Saturated solution: a solution that has dissolved all the solute it normally can hold at a given temperature

Oversaturated solution: any solution that can dissolve more solute at a given temperature

Supersaturated: Contains more solute than a saturated one has at that temperature. Unstable solution

Barrons p 240