Answer: Option (a) is the correct answer.
Explanation:
Sodium has atomic number 11 ans its electronic configuration is [tex]1s^{2}2s^{2}2p^{6}3s^{1}[/tex].
Sodium has one extra electron. Therefore , in order to gain stability sodium readily loses an electron to an electronegative atom. Hence, it becomes stable.
Thus, we can conclude that out of the given options, Na is the most reactive metal.
