Question

Explain the following: 

(i). Why Cs is considered as the most electropositive element? 

(ii). Lithium cannot be used in making photoelectric cells. 

(iii). Lithium does not form alums.

Answer 1

(i). Due to its lowest ionization energy, Cs is considered as the most electropositive element. 

(ii). Lithium cannot be used in making photoelectric cells because out of all the alkali metals, it has highest ionization energy and thus cannot emit electrons when exposed to light. 

(iii). Due to small size, lithium does not form alums.