things to memorize for ap chem

Oxidation number of a free element

0 (e.g., Na, O2, Cl2, Fe(s))

Oxidation number of a monatomic ion

Equal to its charge (e.g., Na+ = +1, Cl- = -1)

Oxidation number of Group 1A metals in compounds

Always +1 (Li, Na, K, Rb, Cs)

Oxidation number of Group 2A metals in compounds

Always +2 (Be, Mg, Ca, Sr, Ba)

Oxidation number of fluorine in compounds

Always -1

Oxidation number of hydrogen (usual case)

+1, except -1 when bonded to a metal (metal hydrides)

Oxidation number of oxygen (usual case)

-2, except -1 in peroxides, -1/2 in superoxides, +2 in OF2

Oxidation number of Cl, Br, I (usual case)

-1, except positive when bonded to oxygen or a lighter halogen

Sum of oxidation numbers in a neutral compound

Equals 0

Sum of oxidation numbers in a polyatomic ion

Equals the charge of the ion

Solubility rule 1

Salts of Group I elements (Li+, Na+, K+, Cs+, Rb+) and ammonium (NH4+) are soluble

Solubility rule 2

Salts containing nitrate (NO3-) are generally soluble

Solubility rule 3

Salts of Cl-, Br-, I- are generally soluble, except halides of Ag+, Pb2+, and Hg2 2+

Solubility rule 4

Most silver salts are insoluble; AgNO3 and Ag(C2H3O2) are the common soluble exceptions

Solubility rule 5

Most sulfates are soluble, except BaSO4, PbSO4, Ag2SO4, and SrSO4

Solubility rule 6

Most hydroxides are only slightly soluble; Group I hydroxides are soluble, Group II (Ca, Sr, Ba) are slightly soluble, transition metal and Al3+ hydroxides are insoluble

Solubility rule 7

Most transition metal sulfides are highly insoluble (e.g., CdS, FeS, ZnS, Ag2S); As, Sb, Bi, and Pb sulfides are also insoluble

Solubility rule 8

Carbonates are frequently insoluble; Group II carbonates (Ca, Sr, Ba), FeCO3, and PbCO3 are insoluble

Solubility rule 9

Chromates are frequently insoluble (e.g., PbCrO4, BaCrO4)

Solubility rule 10

Phosphates are frequently insoluble (e.g., Ca3(PO4)2, Ag3PO4)

Solubility rule 11

Fluorides are frequently insoluble (e.g., BaF2, MgF2, PbF2)

Naming diatomic elements

Just name the element (e.g., H2 = hydrogen, I2 = iodine)

Naming covalent binary compounds (nonmetal/nonmetal)

Name first element (prefix except "mono-"), name second element (prefix including "mono-"), change second element's ending to "-ide"

Prefix for 1

mono-

Prefix for 2

di-

Prefix for 3

tri-

Prefix for 4

tetra-

Prefix for 5

penta-

Prefix for 6

hexa-

Prefix for 7

hepta-

Prefix for 8

octa-

Prefix for 9

nona-

Prefix for 10

deca-

Naming binary ionic compounds

Full cation name first, root of anion name + "-ide" second, Roman numeral if transition metal, simplest ratio balancing charge

Naming ionic compounds with polyatomic ions

Full cation name first, full anion name second, use table for polyatomic ions, simplest ratio, parentheses if more than one polyatomic ion needed

Naming binary acids (H + element)

Hydro + root of element name + "-ic acid" (e.g., HI = hydroiodic acid)

Naming oxyacids where polyatomic ion ends in "-ate"

Change ending to "-ic acid" (e.g., H2SO4 = sulfuric acid)

Naming oxyacids where polyatomic ion ends in "-ite"

Change ending to "-ous acid" (e.g., HClO2 = chlorous acid)

Ammonium

NH4+ (1+)

Cesium

Cs+ (1+)

Copper(I)

Cu+ (1+)

Gold(I)

Au+ (1+)

Hydrogen ion

H+ (1+)

Lithium

Li+ (1+)

Potassium

K+ (1+)

Rubidium

Rb+ (1+)

Silver

Ag+ (1+)

Sodium

Na+ (1+)

Barium

Ba2+ (2+)

Beryllium

Be2+ (2+)

Cadmium(II)

Cd2+ (2+)

Calcium

Ca2+ (2+)

Chromium(II)

Cr2+ (2+)

Cobalt(II)

Co2+ (2+)

Copper(II)

Cu2+ (2+)

Iron(II)

Fe2+ (2+)

Lead(II)

Pb2+ (2+)

Magnesium

Mg2+ (2+)

Manganese(II)

Mn2+ (2+)

Mercury(I)

Hg2 2+ (2+)

Mercury(II)

Hg2+ (2+)

Nickel(II)

Ni2+ (2+)

Strontium

Sr2+ (2+)

Tin(II)

Sn2+ (2+)

Zinc

Zn2+ (2+)

Aluminum

Al3+ (3+)

Antimony(III)

Sb3+ (3+)

Bismuth(III)

Bi3+ (3+)

Chromium(III)

Cr3+ (3+)

Cobalt(III)

Co3+ (3+)

Gallium

Ga3+ (3+)

Gold(III)

Au3+ (3+)

Manganese(III)

Mn3+ (3+)

Nickel(III)

Ni3+ (3+)

Iron(III)

Fe3+ (3+)

Carbon (cation)

C4+ (4+)

Lead(IV)

Pb4+ (4+)

Silicon

Si4+ (4+)

Tin(IV)

Sn4+ (4+)

Antimony(V)

Sb5+ (5+)

Bismuth(V)

Bi5+ (5+)

Acetate

CH3COO- (1-)

Bromide

Br- (1-)

Chlorate

ClO3- (1-)

Chloride

Cl- (1-)

Chlorite

ClO2- (1-)

Cyanide

CN- (1-)

Fluoride

F- (1-)

Hydride

H- (1-)

Hydrogen carbonate (bicarbonate)

HCO3- (1-)

Hydroxide

OH- (1-)

Hypochlorite

OCl- (1-)

Iodate

IO3- (1-)

Iodide

I- (1-)

Nitrate

NO3- (1-)

Nitrite

NO2- (1-)

Perchlorate

ClO4- (1-)

Permanganate

MnO4- (1-)

Thiocyanate

SCN- (1-)

Carbonate

CO3 2- (2-)