atomic radius?

Question

what is the importance of an increase or decrease in atomic radius?

Answer 1

The smaller the atom, the harder it is to remove an electron from it. This is the measure of an atom's ionisation energy.

The smaller an atom (with the exception of the noble gases), the more likely it is to accept an additional electron. This is a measure of its electron affinity.

Both of these concepts factor in when determining whether bonding between two atoms is covalent or ionic.

Answer 2

Why should the atomic size be measured by the distance to the nearest atom of the same element? Would you measure the size of a house by the distance to the house next to it?