Question

what trends are observed in atomic size in modern periodic table when we move (1) down the group (2) across the period why​

Answer 1

Answer:

on moving down the group, from top to bottom, the atomic size increases. This is because with increases in the atomic number , extra shells of electrons are added.

(b) Atomic size refers to the distance from the atomic nucleus to the outermost electron orbit . Atomic size usually increases on going down in a group as the number of shells also increases . But, it decreases on moving left to right across the period due to the shirnking of the atom because of increasing nuclear force