What are Some Common Ions? (Edexcel IGCSE Science (Double Award) (Modular)): Revision Note

Exam code: 4XSD1

Common ions

How to deduce the charge of an ion

  • Find the number of electrons in the outer electron shell

  • Find out if it is easier for the atom to gain electron or to donate electron (in most cases atoms that have fewer than four electrons, donate electrons and atoms that have more than 4 electrons, receive electrons)

  • Atoms that gain electrons become negative ions and atoms that donate electron forms positive ion

  • You also need to learn the formula of compound ions, that is, ions made from more than one element

Common ions with a positive charge

Ion

Charge / formula

Group 1 metals 

1+ (E.g. Na+)

Group 2 metals

2+ (E.g. Mg2+)

Group 3 metals 

3+ (E.g. Al3+)

Silver

Ag+

Copper(II)

Cu2+

Iron(II)

Fe2+

Iron(III)

Fe3+

Lead(II)

Pb2+

Zinc(II)

Zn2+

Hydrogen

H+

Ammonium 

NH4+

Common ions with a negative charge

Ion

Charge / formula

Group 5 non- metals 

3- (E.g. N3-)

Group 6 non- metals 

2- (E.g. O2-)

Group 7 non- metals 

1- (E.g. Cl-)

Hydroxide

OH-

Carbonate

CO32-

Nitrate

NO3-

Sulfate

SO42-

Examiner Tips and Tricks

You must know the charges of all the ions shown in the above tables.

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