Question

how does the atomic size vary in a modern periodic table? give reasons​

Answer 1

on moving left to right in a period atomic size decreases because no. of shells decreases

on moving down in a group atomic size increases because no.of shells increases

Answer 2

On moving down a group the atomic size varies because of the increasing of more shells. On moving down the group the atomic size increases but on moving from left to right the atomic size decreases.

Hope it helps you mate