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A-Level Chemistry - Valency Table
Below is a table of positive and negative ions that you must know for any A-Level Chemistry exam!
Check out these hubs for more help with AS Chemistry revision:
- Electron-Pair Repulsion Theory.
- Trends and the periodic table.
- Calculations and exam questions.
- The basics.
An ion is an atom or molecule with a net electric charge due it losing or gaining one or more electrons.
The loss of electrons is called oxidation and makes the atom/molecule more positive.
The gain of electrons is called reduction and makes the atom/molecule more negative.
If an atom/molecule loses 1 electron it will have a +1 charge, if it loses 2 electrons it will have a +2 charge etc.
This is the same with gaining electrons. If an atom/molecule gains 1 electron it will have a -1 charge and if it gains 2 it will have a -2 charge - it's easy!
Negative Ions (Anions)
Name of ion
| Formula
| Charge
|
|---|---|---|
Chloride
| Cl
| -1
|
Bromide
| Br
| -1
|
Iodide
| I
| -1
|
Hydroxide
| OH-
| -1
|
Hydrogencarbonate
| HCO3
| -1
|
Hydrogensulphate
| HSO4
| -1
|
Nitrate
| NO3
| -1
|
Manganate
| MnO4
| -1
|
Oxygen
| O
| -2
|
Sulphate
| SO4
| -2
|
Sulphite
| SO3
| -2
|
Carbonate
| CO3
| -2
|
Sulphide
| S
| -2
|
Dichromate
| Cr2O7
| -2
|
Phosphate
| PO4
| -3
|
Positive Ions (Cations)
Name of Ion
| Formula
| Charge
|
|---|---|---|
Copper (I)
| Cu
| +1
|
Silver
| Ag
| +1
|
Sodium
| Na
| +1
|
Potassium
| K
| +1
|
Ammonium
| NH4
| +1
|
Hydrogen
| H
| +1
|
Lead (II)
| Pb
| +2
|
Tin (II)
| Sn
| +2
|
Magnesium
| Mg
| +2
|
Calcium
| Ca
| +2
|
Copper (II)
| Cu
| +2
|
Iron (II)
| Fe
| +2
|
Zinc
| Zn
| +2
|
Aluminium
| Al
| +3
|
Iron (III)
| Fe
| +3
|
Lead (IV)
| Pb
| +4
|
Tin (IV)
| Sn
| +4
|
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