Answer: Option (c) is the correct answer.
Explanation:
Atomic number of sodium is 11 and its electronic configuration is [tex]1s^{2}2s^{2}2p^{6}3s^{1}[/tex]. When sodium loses one electron then it will attain +1 charge and its electronic configuration will be as follows.
[tex]Na^{+}[/tex] : [tex]1s^{2}2s^{2}2p^{6}[/tex]
Atomic number of fluorine is 9 and its electronic configuration is [tex]1s^{2}2s^{2}2p^{5}[/tex]. When fluorine gains an electron then it acquires -1 charge and its electronic configuration is as follows.
[tex]F^{-}[/tex] : [tex]1s^{2}2s^{2}2p^{6}[/tex]
Atomic number of aluminium is 13 and its electronic configuration is [tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}[/tex]. When aluminium loses its valence electrons then it acquires +3 charge and its electronic configuration is as follows.
[tex]Al^{3+}[/tex] : [tex]1s^{2}2s^{2}2p^{6}[/tex]
Thus, we can conclude that the listing for aluminum is correct.