The elements that tend to form ionic compounds include cadmium, chromium, cobalt, iron, gold, copper, nickel, manganese, mercury, silver, zinc, tin, bismuth and lead. In the periodic table, these elements belong to the B group of the transition metals and groups IVA and VA of the post-transition metals.
Ionic compounds are formed from the chemical bonding of metals with nonmetals or the combination of metals with polyatomic ions. These compounds consists of electrically charged particles known as ions, which occur when neutral atoms or molecules either gain or lose electrons. Some examples of ionic compounds are ferrous hydroxide, chromium phosphate and mercury(I) chloride.