Question

The configuration of the valence orbital of an element with atomic number 22 is:
A. $3{d^5}4{s^2}$
B. $3{d^2}4{s^2}$
C. $4{s^1}4{p^1}$
D. $3{d^2}4{s^2}4{p^1}$

Answer 1

Hint: The outermost orbital of an atom is known as the valence orbital and the electrons that are present in the valence orbital are known as valence electrons.The element with atomic number 22 is Titanium. After filling the 3p orbital, we see that the orbital will be 4s followed by the 3d orbital.

Complete step by step answer:
For determining the electronic configuration of any element, we build the structures in the order of the atomic numbers. Beginning with hydrogen and continuing across the periods of the periodic table, one proton is added at a time to the nucleus and one electron to the subshell until electronic configuration of all elements is described. This is known as Aufbau rule. Each added electron occupies the subshell of lowest energy available (Pauli exclusion principle) electrons can only enter higher energy subshells after the lower energy subshells have been filled to capacity.
So, after filling the 3p orbital, we see that the orbital will be 4s (it becomes higher in energy than the 3d orbital) followed by the 3d orbital
The element with atomic number 22 is Titanium and it has 22 electrons surrounding the nucleus. It is located in the group 4 and period 4 of the periodic table.
The electronic configuration of Titanium (atomic number = 22) is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^2}4{s^2}$ or [Ar] $3{d^2}4{s^2}$
Therefore, the correct answer is option (B).

Note: The electronic configuration of Titanium (atomic number = 22) is $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^2}4{s^2}$ corresponds to the Aufbau principle. When it will lose electrons, it will happen from 4s orbital first.