Ionic Bonding (Cambridge (CIE) A Level Chemistry): Revision Note

Defining Ionic Bonding

• As a general rule, metals are on the left of the Periodic Table and non-metals are on the right-hand side

• Ionic bonding involves the transfer of electrons from a metallic element to a non-metallic element

• Transferring electrons usually leaves the metal and the non-metal with a full outer shell

• Metals lose electrons from their valence shell forming positively charged cations

Formation of cations

• Non-metal atoms gain electrons, forming negatively charged anions

• Once the atoms become ions, their electronic configurations are the same as a stable noble gas.

  • A potassium ion (K⁺) has the same electronic configuration as argon: [2,8,8]⁺

  • A chloride ion (Cl^-) also has the same electronic configuration as argon: [2,8,8]^- 

Formation of anions

• Cations and anions are oppositely charged and therefore attracted to each other

• Electrostatic attractions are formed between the oppositely charged ions to form ionic compounds

• The ionic bond is the electrostatic attraction formed between the oppositely charged ions, which occurs in all directions

• This form of attraction is very strong and requires a lot of energy to overcome

  • This causes high melting points in ionic compounds

Using cations and anions to form ionic compounds

• The ions form a lattice structure which is an evenly distributed crystalline structure

• Ions in a lattice are arranged in a regular repeating pattern so that positive charges cancel out negative charges

• The attraction between the cations and anions is occurring in all directions

  • Each ion is attracted to all the oppositely charged ions around it

• Therefore, the final lattice is overall electrically neutral

A general ionic lattice