Question

pick the larger species from each pair.

a. Li or Li⁺

b. l^- or Cs⁺

c. Cr or Cr³⁺

d. O or O^2-

Answer 1

a. Li or Li+: Here Li is the larger species. Li has 3 electrons ( 2 on the same level, which is closer to the center of atom, and 1 on second level, outer ), when this atom looses this electron becomes Li+, now the power between protons and these 2 remaining electrons will be stronger, therefore the size will be smaller than Li.

b. l^- or Cs⁺ : Here I^-   is the larger species ( greater the atomic no. greater the size).

c. Cr or Cr³⁺ : here Cr is the larger species (loss of electron decreses the size).

d. d. O or O^2- : Here O^2- is the larger species (addition of elctrons increases the size).