When atom of metal → react with atoms of an non-metal to form an ionic compound → the metallic atoms lose electrons to the non metallic atoms
Energy is required → to remove one mole of valence electrons → from one mole of atoms of metal to form one mole of positive ions. This energy is known as ionisation energy
Size of atoms (and atomic radius) → are also different from the size of ions (and ionic radius) formed by the atoms
Use of Halogens
Fluorine → small amount of fluoride compounds → added to tap water and toothpaste to prevent tooth decay
Chlorine → added to tap water and swimming pools → to destroy bacteria. also used as a bleaching agent
