Question

Arrange the following in decreasing order of their atomic radii: B, O, N, F.

• A. $B>O>N>F$
• B. $B>N>O>F$
• C. $F<O<N<B$
• D. $F<N<O<B$

Answer 1

The correct option is B $B>N>O>F$

Atomic radii generally decreases across a period of elements from left to right due to increase in effective nuclear charge$\left(Z_{eff}\right)$. In a period, the electrons are added to the same shell and at the same time protons are added to the nucleus. The effect of increase proton number is more than increasing electron number which increases the nuclear charge and attracts elelctrons more strongly decreasing the size of elements.
Therefore, correct decreasing order is: $B>N>O>F$