Question

Which is the correct statement for polarisation of the electron cloud of cation is less than anion?
(A) p/e ratio is more than one for anion
(B) p/e ratio is less than one for cation
(C) p/e ratio is more than one for cation by which electrons are relatively loosely held compared to anion
(D) p/e ratio is more than one for cation while less than one for anion by which electron cloud is relatively loosely held for anion

Answer 1

Hint: As we know that polarisation is a phenomenon where a cation is brought near to the anion and the electron cloud of the anion is pulled by the more electronegative cation which results in the deformation in the shape of electron cloud of anion.

Complete Step by step answer: We know that when a cation is brought near to the anion, the attraction between positive charge of cation and negative charge of anion and repulsion between their nuclei and electrons or we can say that electron cloud of the anion is pulled by the more electronegative cation which results into the deformation or distortion in the shape of electron cloud of the anion which is normally spherical, this phenomena is known as the polarisation. It is called polarisability of anion when it gets polarised by cation and the tendency of cation to polarise an anion is its polarising power.
But due to the smaller size and high charge of cation, its polarisation is far less pronounced. In other words we can say that because of the high charge to size ratio of cation it is less polarised. So, due to small size of cation, outermost electrons are tightly held whereas the anion possesses a large size and thus more loosely hold their outermost electrons which makes them prone to distortion of their electron cloud.
Therefore we can say that the p/e ratio is more than one for cation while less than one for anion by which the electron cloud is loosely held for anion.

Thus, the correct answer is (D).

Note: Remember cation is smaller in size due to the loss of electrons from the outermost valence shell and anion is larger in size due to gain of electrons in their outermost valence shell. The charge to size as it is directly proportional to charge and inversely proportional to size depicts that cation possesses the charge to size ratio more than anion.