Question

What is the lowest value of n that allows g orbital to exist?
A.6
B.7
C.4
D.5

Answer 1

For ‘g’ orbital, the value of l=4 where ‘l’ is azimuthal quantum number. The relation between principal quantum number ‘n’ and azimuthal quantum number l’ is such that the value of ‘l’ can be from 0 to (n-1). So we will check the lowest value of n from the given options by using the relation between l and n for the given value of l =4.
Formula Used: Value of ‘l’ can be from 0 to (n-1) where n is Principal quantum number and l is Azimuthal quantum number.

Complete step by step answer:
There are orbitals such as s, p, d, f, g, etc. The value of azimuthal quantum number for them is- For s-orbital = 0
For p-orbital = 1
For d-orbital = 2
For f-orbital = 3
For g-orbital = 4
So corresponding value of ‘n’ for g-orbital will be: As ‘l’ can vary from 0 to (n-1) and we have l =4 for g-orbital so,
$\Rightarrow$ $4 = n-1$
$n = 5.$
Therefore the minimum value of n that allows g-orbital to exist will be 5 out of the given options. The value of n = 4 can’t be considered because g-orbital itself has l = 4 and value of l cannot be equal to value of n. So, the lowest value of n will be 5 for the g-orbital.

Hence, option-(D) is correct.

Note:
Orbital tells us about the most probable location of electrons around the atom in 3-D. The total no. of orbitals for a given subshell equals (2l+1). As for g-subshell the value of l=4 so no. of orbitals present will be 9. Any of these nine orbitals will be called g-orbital. Each orbital can contain a maximum up to two electrons having opposite spins according to the Pauli Exclusion Principle.