The atomic volumes of alkali metals are in the order-
(A) Li > Na > K > Rb > Cs (B) Li > Na = K > Rb > Cs
(C) Li < Na < K < Rb < Cs (D) Li < Na < K < Rb = Cs
(C). As we move from Li to Cs, an extra shell of electrons is added to each element. The addition of an extra shell increases the atomic volume. Therefore, there is an increase of atomic and ionic radii (of ions) from Li to Cs.