Lithium is monovalent . Magnesium is divalent. But Li and Mg are diagonally related pair of elements. Why ?

Lithium is monovalent . Magnesium is divalent. But Li and Mg are diago

1.	Lithium is monovalent . Magnesium is divalent. But Li and Mg are diagonally related pair of elements. Why ?
Answer» Solution :LITHIUM and Magnesium have certain similarities in their properties. Hence, they are CALLED diagonally related pair of elements (a) Li and Mg have simillar ELECTRONEGATIVITY . (b)`Li^(+)` and `Mg^(2+)` have similar POLARISING POWER.