Ionic Bonds

Chemistry: AQA GCSE Higher, topic 2.1.3

Ionic Bonding

When atoms form ions, they try to fill up or empty their outer electron shell. In ionic bonding, a metal atom transfers electrons to a non-metal atom, allowing both of them (the metal and non-metal) to have a full outer electron shell.

Ions formed from Group 1 metals

Group 1 metals lose 1 electron resulting in the formation of positive ions with a charge of +1.
E.g. a sodium atom (Na), with the electronic structure (2,8,1), loses its outer electron when forming an ion to make Na⁺.

Ions formed from Group 2 metals

Group 2 metals always lose 2 electrons resulting in the formation of doubly positive ions.
E.g. a magnesium atom (Mg), with the electronic structure (2,8,2), loses both its outer electrons when forming an ion to make Mg²⁺.

Non-metals (Groups 6 and 7)

Non-metal atoms always gain electrons resulting in the formation of negative ions.
E.g. a fluorine atom (F), with the electronic structure (2,7), will gain an electron when forming an ion to make F^-.

Noble gases (Group 0)

Noble gases already have a full outer shell. Noble gases are unreactive and don't normally form ionic bonds with other elements.

Test yourself on Ionic Bonds

Why are noble gases not usually involved in ionic bonding?
A fluorine atom has the electronic structure 2,7. What electronic structure does a fluoride ion (F-) have after it gains one electron?
Why does a magnesium ion have a greater charge than a sodium ion?
What is true about the charges on a sodium ion (Na+) and a fluoride ion (F-)?

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