Chapter 2: Chemical formula/Polyatomic Ions

Chemical formula

shows the chemical composition of the substance.

He, Au, Na- what type of elements

monatomic elements

O₂, H₂, Cl₂-what type of element

diatomic elements

O₃, P₄, S₈- what type of element are they?

complex elements

H₂O, C₁₂H₂₂O₁₁ - what type of element are they

compounds

Two basic types of ions:

cations; anions

cations

Positive ions

anions

Negative ions

non-metals form _______

anions

Some metals can form multiple types of _____

Cation

Type I cations

metals that only form one cation

These are main group metals (IA, IIA, IIIA) and some
exceptions from the transition metals: what are they?

Ag, Cd, Zn

Type II cations

metals that can form more than one cation

Polyatomic Ions

group of atoms with a charge

Acetate

C₂H₃O₂⁻

Carbonate

CO₃²⁻

Hydrogen Carbonate

HCO₃⁻

Hydroxide

OH⁻

Nitrite

NO₂⁻

Nitrate

NO₃^-

Chromate

CrO₄²⁻

Diachromate

Cr₂O₇²⁻

Phosphate

PO₄³⁻

Hydrogen phosphate

HPO₄²⁻

Dihydrogen phosphate

H₂PO₄⁻

Ammonium

NH₄⁺

Hypochlorite

CIO⁻

Chlorite

CIO₂⁻

Chlorate

CIO₃⁻

Perchlorate

CIO₄⁻

Permanganate

MnO₄⁻

Sulfite

SO₃²⁻

Hydrogen sulfite

HSO₃⁻

Sulfate

SO₄²⁻

Hydrogen Sulfate

HSO₄⁻

Cyanide

CN⁻

Peroxide

O₂²⁻

Empirical Formula

smallest whole-number ratio of atoms present in a compound

Molecular Formula

actual numbers of atoms of each
element present in a molecule of the compound

Ionic compounds

neutral compounds formed by the attraction between cations (usually metals) and anions.

Type I metal with a non-metal use the following
convention

get ide ending

Type II metal

specify the charge on the metal with a roman numeral after the cation

Higher charge ion is given the ending

–ic

Lower charge ion is given the ending

–ous

Hydrates

ionic compounds that also contain water

Avogadro’s number

6.022 x 10²³ things (atoms, ions,
marbles, students, etc)

Relative atomic mass (RAM)

the weighted average of the masses of an element’s isotopes.

Isotopes

atoms with the same element with the same number of protons but different number of neutrons

Moles to

grams

Avagadro’s number = 

mole

Percent composition

the mass of an individual element in a compound

intrinsic property

Percent composition