Question

Arrange giving reasons, the species Cl, Cl+ and Cl- in order of 

a. Increasing size

b. Increasing electron affinity

Answer 1

a) Increasing size;

Cl⁺ , Cl, Cl^-

This is because, although all the species have the same number of filled energy levels and similar nuclear charges, they have differing numbers of electrons in their outer shells.

Cl+ has the least number of outer shell electrons and therefore the electrons experiences the least shielding effect and electron-electron repulsions, hence the least size.

Cl comes in the middle and Cl- has the largest number of electrons in the outer shell. The higher the number of electrons in the outer shell, the greater the shielding effect and electron-electron repulsions, hence the particle tends to bulge.

b) Increasing electron affinity

Cl^-, Cl, Cl⁺

Cl- has an extra electron and its outer shell is completely filled with electrons, hence has the lowest tendency to attract another electron.

Cl has the middle tendency, while Cl+ has the highest tendency to attract an electron. This is because Cl+ is electron defficient and hence the greatest electron affinity