Arrange the elements of period 3 in decreasing metallic character.

Explanation

Generally moving from left to right across any period metallic character decreases, e.g.: `Na gt Al gt Mg gt Si gt S gt P gt Cl gt Ar`
However, Al is more metallic than Mg because I.E. of Al (= 578 kJ/mol) is less than Mg (=738 kJ/mol) Similarly, S is more metallic than P.