Polyatomics and solubility

OH^-

hydroxide

CN^-

cyanide

SCN^-

thiocyanate

ClO^-

hypochlorite

ClO₂^-

chlorite

ClO₃^-

chlorate

ClO₄^-

perchlorate

C2H3O2^- or CH3COO^-

acetate

C₂O₄^2-

oxalate

S₂O₃^2-

thiosulfate

CrO₄^2-

chromate

Cr₂O₇^2-

dichromate

NO₂^-

nitrite

NO₃^-

nitrate

SO₃^2-

sulfite

SO₄^2-

sulfate

O₂^2-

peroxide

CO₃^2-

carbonate

HCO₃^-

hydrogen carbonate or bicarbonate

PO₃^3-

phosphite

PO₄^3-

phosphate

NH₄⁺

ammonium

Steric number 1

AX, linear, 180^o

Steric number 2

AX₂, linear, 180^o

Steric number 3

AX₃, trigonal planar, 120^o

AX₂E, bent, <120^o

Steric number 4

AX₄, tetrahedral, 109.5^o

AX₃E, pyramidal, <109.5^o

AX₂E₂, bent, <109.5^o

Steric number 5

AX₅, trigonal bipyramidal, 90^o and 120^o

AX₄E, see-saw, <100^o and <180^o

AX₃E₂, T-shaped, ~90^o

AX₂E₃, linear, 180^o

Steric number 6

AX₆, octahedral, 90^o

AX₅E, square pyramidal, ~90^o

AX₄E₂, square planar, ~90^o

Formal charge

FC = #valence e^- - #e^- in lone pairs - #bonds to atom

Steric number

#of X + #lone pairs

Bond order

½ (#e^- in bonding orbitals - #e^- in antibonding orbitals)

Paramagnetic

has unpaired e^-

Diamagentic

no unpaired e^-

Pauli exclusion principle

2e^-/orbital max

Hund’s rule

start e^- in lower E orbitals, don’t pair until necessary (e^- - e^- repulsion)

Quantum number n

size, correlates to shells

Quantum number l

shape, takes on values from 0 to n-1

Quantum number m_i

spatial orientation, takes on integer values from -l to l

Quantum number m_s

spin, either +½ or -½

Atomic radius periodic trend

increases going down a group in the table

Ionization energy period trend

decreases going down a group in the table

Electronegativity period trend

Increases going up a group and right in a period

Electron affinity period trend

more negative going right in a period and up a group

Pure covalent bond/nonpolar bond

electronegativities are nearly the same or <0.4 difference

Polar covalent bond

electronegativites differ by 0.4 or more, e^- not shared equally

Pure ionic bond

difference in electronegativites is >2.0, e^- pair completely on more electronegative atom

Partial charges (δ)

more electronegative atom attracts e^- pair more, giving it partial -δ, other atom will have partial +δ

Partial ionic character

greater likelihood e^- in covalent bond will be near one atom over the other

Dipole moment

arrow pointing along bond from -δ to +δ, measures polarity of diatomic molecule, nonpolar has no net dipole moment

% ionic character

Observed δ/calculated δ x 100%

[1-e^{-0.25(difference in electronegativity)}] x 100%

Solubility rule 1

Alkali metal salts and ammonium salts - soluble

Solubility rule 2

Nitrates, acetates, perchlorates - soluble

Solubility rule 3

Silver, lead, mercury(I) salts - insoluble

Solubility rule 4

Chlorides, bromides, iodides - soluble

Solubility rule 5

Carbonates, chromates, sulfides, oxides, phosphates, hydroxides (except BaCaSr) - insoluble

Solubility rule 6

Sulfates (except BaCaSr) - soluble

Nonmetal reactivity period trend

Increasing going up and right

Metal reactivity periodic trend

Decreasing going up and right

General reactivity order

Li, K, Ba, Ca, Na, Mg, Al, Mn, Zn, Cr, Fe, Co, Ni, Sn, Pb, Cu, Hg, Ag