Question

The electron distribution in an aluminium atom is:

• A. $2,8,3$
• B. $2,8,2$
• C. $8,2,3$
• D. $2,3,8$

Answer 1

The correct option is A

$2,8,3$

Explanation for the correct option:

Option A: $2,8,3$:

Electronic Configuration:

1. The electronic configuration is the distribution of electrons in various energy levels or shells of an atom of the element. The shells are also called energy levels.
2. The shell closest to the nucleus is $\mathrm{K}$ shell, the next shells are $\mathrm{L}$ shell, $\mathrm{M}$ shell and $\mathrm{N}$shell.
3. The $\mathrm{K}$ shell, $\mathrm{L}$ shell, $\mathrm{M}$ shell and $\mathrm{N}$shell can accommodate $2,8,18$and $32$ electrons respectively.

Electronic configuration of Aluminium $\mathbf{\left(}\mathbf{Al}\mathbf{\right)}$:

1. The Aluminium atom has atomic number $13$. Thus, Aluminium atom has $13$ electrons.
2. The $\mathrm{K}$ shell accommodates $2$ electrons, $\mathrm{L}$ shell accommodates $8$ electrons and the remaining $3$ electrons go in the $\mathrm{M}$ shell.
3. The electronic configuration of Aluminium atom is $2,8,3$.

Explanation for the incorrect options:

Option B: $2,8,2$:

The electronic configuration $2,8,2$ belongs to the Magnesium atom $\mathbf{\left(}\mathbf{Mg}\mathbf{\right)}$.

Option C: $8,2,3$:

The first shell cannot have eight electrons.

Option D: $2,3,8$:

The second shell should be completely filled before the electron enters the third shell.

Hence, Option (A) is the correct option.