Question

Write the number of periods and groups in the modern periodic table how does the metallic character of elements vary on moving from left to right in a period and down a group give reasons to justify your answers

Answer 1

periods---7

groups ---18

on moving left to right in a period the metallic character decreases

reason

-as nuclear charge increases in a period the tendency of atoms to loose electrons decreases. the electron are pulled in more strongly by the nucleus and it becomes difficult to loose electrons

on moving down agroup metallic character increases

reason

as nuclear charge decrases the tendency to loose electrons increases. the valence electrons are held loosely by the nucleus and it becomes easy to loose electrons