Question

Why does atomic radius decrease from left to right across a period and what are the ionic radius trend: cation and anion

Answer 1

Atomic radius decreases from left to right in a period because,on moving in a period no of electrons are added in the valence shell and these electrons are attracted towards the nucleus of each atom,due to this attractive forces the atom size decreases,and atomic radius also decreases. First ion is formed due to loss or gain electrons from the atom,if loss cation is formed,if gain anion is formed,. Ionic radius means the distance between centre of nucleus of cation or anion to valence shell in which last electron present. In case of cation,loss of electron takes place and the nuclear charge increases,due to it attracts more powerful the last electron then ionic radius decreases,but in case of anion,the nuclear charge decrease s due to that last valence shell has more electron than atom,so ionic radius increases.