Question

Which ion does not have a noble gas configuration in its ground state? which ion does not have a noble gas configuration in its ground state? al3+ sc3+ as3- ga3+?

Answer 1

The correct answer is Ga3+.  

Electron configuration of Al is [Ne] 3s2 3p1  

Electron configuration of Al3+ is [Ne]  

So the electron configuration of Al3+ is like that of Ne.  

Electron configuration of Sc is [Ar] 3d1 4s2  

Electron configuration of Sc3+ is [Ar]  

So the electron configuration of Sc3+ is like that of Ar.  

Electron configuration of As is [Ar] 3d10 4s2 4p3  

Electron configuration of As3- is [Ar] 3d10 4s2 4p6

So the electron configuration of As3- is like that of Kr

Electron configuration of Kr [Ar] 3d10 4s2 4p6  

Electron configuration of Ga is [Ar] 3d10 4s2 4p1

Electron configuration of Ga3+ is [Ar]3d10

The presence of the ten d orbital electrons prevents Ga3+ from having the same electron configuration as Argon.  

All other choices have the same electron configurations as a noble gas.  

Answer 2

Answer: Option (d) is the correct answer.

Explanation:

The atomic number of Al is 13, so the electronic configuration of $Al$ is as follows.

            $1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}$

         = $[Ne]3s^{2}3p^{1}$

$Al^{3+}$ = [Ne]

The atomic number of Sc is 21, so the electronic configuration of $Sc$ is as follows.

         $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{1}$

        = $[Ar]4s^{2}3d^{1}$

 $Sc^{3+}$ = [Ar]

The atomic number of As is 33, so the electronic configuration of $As$ is as follows.

         $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{3}$

         = $[Ar]4s^{2}3d^{10}4p^{3}$

 $As^{3-}$ = $[Ar]4s^{2}3d^{10}4p^{6}$ = [Kr]

The atomic number of Ga is 31, so the electronic configuration of $Ga$ is as follows.

        $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{1}$

       = $[Ar]4s^{2}3d^{10}4p^{1}$

 $Ga^{3+}$ = $[Ar]3d^{10}$

Therefore, we can conclude that galium (Ga) ion does not have a noble gas configuration in its ground state.