common cations and anions + common polyatomic ions

nitrite vs nitrate

NO₂ ^- vs NO₃ ^-

amonium

NH₄⁺

sulfite vs sulfate

SO₃^2- vs SO₄^2-

phosphate vs hydrogen phosphate vs dihydrogen phosphate

PO₄^3- vs HPO₄^2- vs H₂PO₄^-

OH^-

hydroxide

CN^-

cyanide

CO₃^2-

carbonate

hydrogen sulfate/ bisulfate

HSO₄^-

hydrogen carbonate / bicarbonate

HCO₃^-

hypochlorite

ClO^- or OCl^-

chlorite vs chlorate

ClO₂^- vs ClO₃^-

ClO₄^-

perchlorate

acetate

C₂H₃O₂^-

Mercury (I)

Hg₂²⁺

*Thiocyanate

NCS^- or SCN^-

permanganate

MnO₄^-

dichromate vs chromate

Cr₂O₇^2- vs CrO₄^2-

thiosulfate

S₂O₃^2-

peroxide

O₂^2-

oxalate

C₂O₄^2-

rules for ionic, gr 1&2 metals

metal name + ide suffix at end