Question

Atomic size decreases across a period but increases down a group in periodic table

Answer 1

Atomic radius is the distance between the centre of the atom and its outermost shell.

New shells are added to the atoms of elements as we go down in from top of bottom in a group.

The outermost electrons go further and further away from the nucleus,extending the radius and ultimately increasing the size of the atom.hence,atomic radius goes on increasing down a group