“Whether you think you can, or you think you can’t - you’re right.”

- Henry Ford

Review ofChapter 1: The Atom

History of Atomic Theories

Parts of an AtomNucleus

Protons: positive charge, mass = 1 amu Neutrons: no charge, mass = 1 amu

Electrons Negative charge, mass = 0 amu Valence e- are the outermost ones Located somewhere in orbitals, regions of e-

density

amu is an “atomic mass unit”, a unit of weight

Remember: # protons = # electrons in uncharged atoms

Atomic Number

Atomic number is

# of protons

(and # of electrons)

Mass number is

# of protons and

neutrons combined, gives “weight” of atom

Isotopes

Isotopes are different versions of the same element Same atomic number (# protons) Different mass number (from different # neutrons)

H-1 H-2 H-3

Calculating Atomic Mass

(amu-1)(%1) + (amu2)(%2) + (amu3)(%3) + …

Electron Locations

Electrons are in orbitalsGround state is the

lowest levelElectrons can absorb

energy and move to a higher level, or excited state

Release energy as they drop back down

Review ofChapter 2: Formulas

and Equations

Formula BasicsSymbols identify elements: K, Na, O, F, Mg, SbFormulas give info from symbols and numbers

NaCl NH3 CH3Br

Qualitative info can’t be counted (quality). Ex: what elements are present

Quantitative info can be counted (quantity). Ex: how much of each element?

Writing Formulas

Coefficients are written in front of a formula, tells how many of the formula there are

3 CO2 5 H2O 8 NH3

Subscripts are small, after symbols, and tell how many atoms there are of each element

3 CO2 5 H2O 8 NH3

Ions

Uncharged atoms have same #

of protons and electronsIons are atoms that lose or gain electrons,

become charged:

Cl-, Na+, Cu Polyatomic ions are charged molecules:

NH4+, SO4 , NO3-

2+

2-

Equalizing Charges

Naming Compounds

Ionic (M/NM) compounds: use name of (+) element (metal), change end of (-) nonmetal to “-ide.” Ex: NaCl = Sodium chloride

Polyatomic ions keep their namesCovalent (NM/NM) compounds: less

electronegative atom written first, each is named with “mono-, di-, tri-, tetra-” prefixes. Ex: N2O4 = Dinitrogen tetroxide

Roman Numerals in Names

Use a numeral in names when an atom has several options of what its charge can be

Copper (III) sulfate means the copper atom has a +3 charge, as opposed to other possible charges. Cu2(SO4)3

Lead (II) nitrate = Pb(NO3)2

Ch-ch-ch-changes

Physical changes affect form of starting material, but stays same substance Cheese melting, chopping wood

Chemical changes produce new substances Burning wood, mixing acid & base

Chemical Reaction Equations

Reactant + Reactant Product + Product

HCl + NaOH H2O + NaCl

Law of Conservation of Mass says whatever’s on the left needs to be on the right, nothing created or destroyed

4 Types of ReactionsAddition: A + B C

Things come together

Decomposition: C A + B Something breaks apart

Single Replacement: AB + C A + BC Part of a compound is replaced

Double Replacement: AB + CD AD + BC All the pieces of a compound switch around