An atom is electrically neutral but still it has a tendency to form an ion. While forming an ion it is observed that the size of cation is smaller while the size of an anion is bigger than the atom. Explain

Explanation

Though the atoms are electrically neutral, yet most of them do not have all the energy shells completely filled up. Therefore they accept or lose electrons to acquire the stable electronic configuration of the nearest noble gas. A cation is formed when atom loses its electrons from the valence shell which results in decrease in number of shells reducing the size of the atom. When an anion is formed, a neutral atom accepts one or more electrons in the valence shell to get stable nearest noble gas configuration. This results in increase in number of electrons while protons remain same which decreases the force of attraction between the nucleus and the electrons hnece the size of anion increases
`{:(Na-e^(-),rarr,Na^(+)),("2,8,1",,"2,8"),((11e^(-)","11p),,(10e^(-)","11p)),(Cl+e^(-),rarr,Cl^(-)),("2,8,7",,"2,8,8"),(17 e^(-)","17p,,(18e^(-)","17p)):}`