Which of the following elements contains maximum number of unpaired electrons?

Step-by-step solution

To identify the element with the maximum unpaired electrons, electron configurations are analyzed using Hund's rule. Fluorine ( Z=9 ) has configuration 1s^2 2s^2 2p^5 , yielding one unpaired electron: Sodium ( Z=11 ) has 1s^2 2s^2 2p^6 3s^1 , with one unpaired electron: Nitrogen ( Z=7 ) has 1s^2 2s^2 2p^3 , resulting in three unpaired electrons: Oxygen ( Z=8 ) has 1s^2 2s^2 2p^4 , producing two unpaired electrons: Nitrogen exhibits the maximum with three unpaired electrons. The correct choice is C .