Question

The set of elements that differ in diagonal relationship from those of the other sets is

• A. B - Si
• B. Li - Na
• C. Be - AI
• D. Li - Mg

Answer 1

The correct option is B Li - Na

Due to similar size of Li and Mg they show similar properties.
The ionic radius of $B{e}^{2+}$ is estimated to be 31 pm; the charge/radius ratio is nearly the same as that of the $A{l}^{3+}$ ion. Hence beryllium resembles aluminium in some ways.
Due to its small size and similar charge/mass ratio, boron varies from other group 13 members, but it resembles to the silicon, the second element of the group 14 to exhibit diagonal relationship.



Li - Na belong to same group