Which of the following has the largest atomic radius?

Options

A. `C`
B. `P`
C. `Si`
D. `N`

Answer

C

Explanation

Note that `C` and `Si` are in the same group (group `14`) so that the radius of `C` is smaller than that of `Si` (atomic radius increases as we go down a group). Both `N` and `P` are in the same group, thus, the radius of is smaller than that of `P`. Both `C` and `N` are in the second period, and `C` is to the left of `N`. Therefore, the radius of `N` is smaller than that of `C` (atomic radius decreases as we move from left to right across a period). Similarly, both `Si` and `P` are in the third period and `Si` is to left of `P`, therefore, teh radius of `P` is smaller than that of `Si`. Thus, the order of increasing radius is `N lt C lt P lt Si`.