Why the metallic or non metallic character of elements vary depending upon their position in the periodic table?

the metallic character of element vary in a periodic table due to their electronic configuration & ionic capacity.

as,we move down a period the the number of electrons increase by 1 following the other . the metal with outermost electrons 1,2 3 give electrons in order to achieve the stable electronic structure "octave "  .hence the metal having 1 electron can give electron fast then the metal with 3 electron.

ex-  Na- 2,8,1  &  Al- 2,8,2

Na is more reactive then al

as we go down a group the metallic character increase for metals & decrease of nonmetals.

as we go in a period the metallic character decrease while the non metallic character increase.

"for better reference follow the international hloy faith.