• # question_answer Which one of the following is expected to have largest size [UPSEAT 2004] A) ${{F}^{-}}$ B) ${{O}^{-2}}$ C) $A{{l}^{+3}}$ D) ${{N}^{-3}}$

Due to having three electrons atomic size increases. ${{F}^{-}}=9+1=10$ electrons ; ${{O}^{-2}}=8+2=10$ electrons $Al+3=13-3=10$ electrons ; ${{N}^{3-}}=7+3=10\,{{e}^{-}}.$ Because electrostatic force between nucleus and $\bar{e}$ cloud is least in nitrogen.