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A-Level Chemistry - Valency Table

Updated on January 7, 2013

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:

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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    • Anthropophobia profile image
      Author

      Anthropophobia 4 years ago

      Thank you!

    • KA Pederson profile image

      Kim Anne 4 years ago from Texas

      Great mini refresher! Voting you up for "useful" :)