Question

Why are metallic character decreases across a period and increases down a group​

Answer 1

Answer:

Down the group, the effective nuclear charge experienced by valence electrons decreases because the outermost electrons move further away from the nucleus. Therefore, these electrons can be lost easily. Hence, metallic character decreases across a period and increases down a group.

Answer 2

Answer:

Metallic character decreases across a period because the elements that have 1,2 or 3 electrons in the outermost shell they donate their atoms and become electropositive where as the elements that have 5,6 or 7 electrons in the outermost shell they gain electrons and become electronegative. Metallic elements are electropositive whereas non-metallic elements are electronegative. Therefore it decreass across a period. It increases down a group because the elements down the group become more electropositive by donating electrons.

hope its helps..