Ions table
Cations: Positive ions.
| Hydrogen ion | H+1 |
| Lithium | Li+1 |
| Sodium | Na+1 |
| Potassium | K+1 |
| Rubidium | Rb+1 |
| Cesium | Cs+1 |
| Magnesium | Mg+2 |
| Calcium | Ca+2 |
| Strontium | Sr+2 |
| Barium | Ba+2 |
| Aluminum | Al+3 |
| Chromium | Cr+2 (Chromus) |
| Chromium | Cr+3 (Chromic) |
| Manganese | Mn+2 (Manganous) |
| Manganese | Mn+3 (Manganic) |
| Iron | Fe+2 (ferrous) |
| Iron | Fe+3 (ferric) |
| Cobalt | Co+2 (Cobaltous) |
| Cobalt | Co+3 (Cobaltic) |
| Nickel | Ni+2 (nickelous) |
| Nickel | Ni+3 (nickelic) |
| Zinc | Zn+2 |
| Silver | Ag+1 |
| Gold | Au+3 (Auric) |
| Platinum | Pt+2 (platinous) |
| Platinum | Pt+4 (platinic) |
| Tin | Sn+2 (Stannous) |
| Tin | Sn+4 (Stannic) |
| Lead | Pb+2 (plumbous) |
| Lead | Pb+4 (plumbic) |
| Arsenic | As+3 |
| Antimony | Sb+3 |
| Bismuth | Bi+3 |
| Palladium | Pd+2 |
| Cadmium | Cd+2 |
| Mercury | Hg+2 (Mercuric) |
| Mercury | Hg2+2 (Mercurous) |
| Ammonium | NH4+1 |
For a particular metal atom the name of the ion with less charge ends with ’ous’ and the name of the ion with high charge end with ‘ic’. Example Fe+2, ferrous and Fe+3 ion is ferric.
Anions: Negative ions.
| Hydride | H-1 |
| Boride | B-3 |
| Carbide | C2-2 |
| Nitride | N-3 |
| Phosphide | P-3 |
| Oxide | O-2 |
| Sulphide | S-2 |
| Fluoride | F-1 |
| Chloride | Cl-1 |
| Bromide | Br-1 |
| Iodide | I-1 |
| Cyanide | CN-1 |
| Hydroxide | OH-1 |
| Peroxide | O2-2 |
| Cyanate | CNO-1 |
| Thio Cyanate | CNS-1 |
| Aluminate | AlO3-3 |
| Meta aluminate | AlO2-1 |
| Borate | BO3-3 |
| Metaborate | BO2-1 |
| Carbonate | CO3-2 |
| Bicarbonate | HCO3-1 |
| Silicate | SiO3-2 |
| Nitrite | NO2-1 |
| Nitrate | NO3-1 |
| Phosphate | PO4-3 |
| Phosphite | PO3-3 |
| Hydrogen Phosphate | HPO4 −2 Adding two H+1 to PO43- ion |
| Dihydrogen Phosphate | H2PO4– Adding one H+1 to PO43- ion |
| Arsenate | AsO4-3 |
| Arsenite | AsO3-3 |
| Sulphate | SO4-2 |
| Sulphite | SO3-2 |
| Bisulphate | HSO4-1 Adding one H+1 to SO42- ion |
| Bisulphite | HSO3-1 Adding one H+1 to SO32- ion |
| Thiosulphate | S2O32- |
| Perchlorate | ClO4-1 |
| Chlorate | ClO3-1 |
| Chlorite | ClO2-1 |
| Hypochlorite | ClO-1 |
| Bromate | BrO3-1 |
| Bromite | BrO2-1 |
| Hypobromite | BrO-1 |
| Iodate | IO3-1 |
| Iodite | IO2-1 |
| Chromate | CrO4-2 |
| Dichromate | Cr2O7 −2 |
| Permanganate | MnO4-1 |
| Zincate | ZnO2-2 |
| Acetate | CH3COO-1 |
| Oxalate | C2O4-2 |
| Formate | HCOO-1 |
| Amide | NH2-1 |
| Ferro Cyanide | [Fe(CN)6]4- |
| Ferri Cyanide | [Fe(CN)6]3- |
In case of anions if the name ends with ‘ide’ it contains atoms of the same element.
There are some exceptions like cyanide (CN-1), amide (NH2-1), hydroxide (OH-1) thio hydroxide (SH-1) etc.
Anions containing oxygen are called Oxoanions
If the name ends with ‘ite’ or ‘ate’ it contains oxygen.
If the name ends with ‘ite’ it contains less number of oxygen atoms.
If the name ends with ‘ate’ it contains more number of oxygen atoms.
Example: Nitrite NO2-1. Nitrate NO3-1.
You can observe many in the above list.
Dear learners.
It is not necessary to mug up all these formulas. When do exercises using them automatically you remember them. Do we have to mug up our family and friends names?
Using the above formulae of ions we can write the name of their corresponding compounds as follows.
Calcium chloride = Ca+2 Cl-1.
Now to get the formula inverse numbers but not charges.
So the formula is CaCl2.
Calcium phosphate = Ca+2 PO43-
Now to get the formula inverse numbers but not charges.
The formula of the compound is Ca3 (PO4)2.
When the charges are identical inversing is not needed.
For example consider Aluminium Borate = Al+3 (BO3)3- . Its formula is Al(BO3).
Writing Chemical Formula of Binary Compounds using Valency
A Chemical formula represents the proportions, by mass of the different elements in a compound.
A binary compound is composed of two different elements only. Formulae of binary compounds can be written using valencies since both types of atom forming the compound must lose, gain or share the same number of electrons.
- To write the chemical formula of a binary compound.
- Determine the valencies of the two elements present.
- Write the chemical formula such that the sums of the valencies of the two elements are equal. Do this by determining the lowest common multiple of the two valencies.
- If a metal is present, always place it first in the formula.
Solved Examples
1. Aluminium oxide
Valencies of elements:
Al = 3 (Group III)
O = 2 (Group VI)
Lowest common multiple of valencies = 6
Al = 2 x 3 = 6
O = 3 x 2 = 6
Therefore the chemical formula = Al2O3
2. Phosphorus trichloride
Valencies of elements:
P = 3 (Group V)
Cl = 1 (Group VII)
Lowest common multiple of valencies = 3
P = 1 x 3 = 3
Cl = 3 x 1 = 3
Chemical formula = PCl3