Question

Arrange the following elements in the order of the increasing electropositive character.

$Li,Na,K,Rb,Cs$

• A. Li > Na > K > Rb > Cs
• B. Li < Na < K < Rb < Cs
• C. Li > Na < K < Rb < Cs
• D. Na > Li > K < Rb < Cs

Answer 1

Answer: (B)

Li < Na < K < Rb < Cs

All the alkali metals have one valence electron, $n{s}^1$ outside the noble gas core electronic configuration. The loosely held $s$-electron in the outermost valence shell of these elements makes them the most electropositive metals. They readily lose an electron to give monovalent $M^{+}$ ions. Hence they are never found in the free state in nature.

The electropositive nature of alkali metals increases down the group.

Hence, the correct option is $\text{B}$.