In group- The electropositive or metallic characters increases from top to bottom in a group .
ELECTRO-NEGATIVE OR NON- METALLIC CHARACTERS : the tendency of an element to accept electrons to form an anion is called its non metallic or electronegative character . The elements having high electro-negativity have higher tendency to gain electrons and forms anion . So , the elements in the upper right hand portion of the periodic table are electro-negative or non-metallic in nature .
Periodicity :
( i ) In period- The electro-negative or non- metallic characters increases from left to right in a period .
( ii ) In group- The electro-negative or non-metallic characters decreases from top to bottom in a group .
REACTIVITY OF METALS : Periodicity :
( i ) In period- The tendency of an element to lose electrons decreases in a period . So the reactivity of metals decreases from left to right in a period .
( ii ) In group- The tendency of an element to lose electrons increases in a period . So the reactivity of metals increases from top to bottom in a group .
REACTIVITY OF NON- METALS :
( i ) In period- The tendency of an element to gain electrons increases in a period . So the reactivity of non-metals increases from left to right in a period .
( ii ) In group- The tendency of an element to gain electrons decreases in a group . So the reactivity of non-metals increases from top to bottom in a group .