Formula of Ions

  1. Ionic compounds made up of positive ions and negative ions.
  2. To write the formula of an ionic compound, we need to know the symbol and charge of the ions in the compound.
Positive ions that you need to know in SPM form 4 chemistry:
Ion
Symbol
Ion
Symbol
Ion
Symbol
Potassium
K+
Calcium
Ca2+
Aluminium
Al3+
Sodium
Na+
Magnesium
Mg2+
Iron (III)
Fe3+
Lithium
Li+
Zinc
Zn2+
Hydrogen
H+
Barium
Ba2+

Argentums(I)
Ag+
Iron (II)
Fe2+
Mercury(I)
Hg+
Tin (II)
Sn2+

Ammonium
NH4+
Lead(II)
Pb2+

Copper(II)
Cu2+
Manganese(II)
Mn2+


Negative ions that you need to know in SPM form 4 Chemistry
Sulphate
Carbonate
Nitrate
Hydroxide
SO42-
CO32- NO3- OH-

Fluoride
Chloride
Bromide
Iodide
Oxide
F-
Cl-
Br-
I-
O2-

Negative ions that you need to know in SPM form 5 Chemistry
Phosphate Ethanoat Manganate(VII) Dichromate(VI) Thiosulphate
PO43-
CH3COO-
MnO4-
Cr2O72-
S2O32-