oxidation state

Generally in a group oxidation state remains the same.(oxidation state refers to the charge which appears on an atom in a molecule when all other bonded atoms are removed as ions). eg. all members of group 1 exhibit +1 oxidation state. But in certain groups members exhibit variable oxidation states as well. eg.members of B family exhibit +1 as well as +3 oxidation states. As we go down the group lower oxidation state becomes more stable due to inert pair effect.