Question

What is shorthand electron configuration of $ Al $ ?

Answer 1

Hint: To solve the given question, the concepts to be cleared are about Quantum number, shells, sub-shells, orbitals, Pauli Exclusion Principle, Aufbau Rule and P fund's Rule.
Quantum number is basically the address of an electron in an atom.Shells are the permitted orbits where an electron revolves with fixed angular momentum. Subshell is a division under a shell which contains orbital or orbitals.

Complete step by step solution:
Step-1 :
The formula for aluminium is $ Al $ . Here,the total number of electrons is $ 13 $ .
Step-2 :
The four quantum numbers are Principal Quantum Number which denotes the shell, Azimuthal Quantum Number denoting sub-shell, Magnetic Quantum Number and Spin Magnetic Number.
The sub-shells are s,p,d,f, . . . . . . and so on. They are filled on the basis of energy with $ n+l $ rule.
Step-3 :
So, $ Al $ can be represented as $ 1s^22s^22p^63s^23p^1 $ . The above given configuration is long form. To write it in shorthand, we look at the nearest noble gas, where it is neon.
So, shorthand electron configuration is $ [Ne]3s^23p^2 $ .

Additional Information:
Pauli’s Exclusion Principle states that any $ 2 $ electron can never have all the same $ 4 $ quantum numbers.
Aufbau Rule explains the filling of electrons according to energy level.
P fund’s Rule explains that every orbital with one electron then fills another electron.
The magnetic quantum number differentiates orbitals in a given subshell. The l is always less than shell when $ l=0,s;l=1,p;l=2,d;l=3,f; $ and so on.
 $ 2 $ Electrons are present in s, $ 6 $ in p, $ 10 $ in d and $ 14 $ in f.

Note:
During the electronic configuration, always make sure to write with inner to outer shells but fill the electron according to energy. The energy of $ 3d $ is more than $ 4s $ but $ 3d $ is written inner to $ 4s $.