Positive and negative ions form during some reactions. Ionic compounds are usually formed when metals react with non-metals.
The ions formed are held to each other by enormously strong forces of attraction between the oppositely charged ions.
1. Ionic compounds are held together by strong forces between the oppositely charged ions.
2. Other elements that can form ionic compounds include those in Group 2 and 6.
Common salt in sodium chloride. In just 58.5g of salt there are over 600 000 000 000 000 000 000 000 ions of Na+ and the same number of Cl- ions.
The structure of ionic lattice is investigated by passing X-rays through them.