Question

g orbital is possible if:
A. n=5, l=4
B. it will have 18 electrons
C. it will have 9 types of orbitals
D. it will have 22 electrons

Answer 1

This question is based on the periodic table and quantum numbers. In order to solve this question, we should consider the range of different quantum numbers and the electrons and orbitals they contain. An orbital always has only ‘two’ electrons in it. The total number of orbitals are (2l+1) orbitals

Complete step by step answer:
Let us first discuss the types of quantum numbers and their definitions and ranges.

Types of Quantum Numbers	Definitions	Symbols	Possible values	Total values or the count
Principal Quantum Number	Designate the principal shell of an electron of the atom.	n	1,2,3,….	It is always a positive natural number. It is generally 0 to 7 in the periodic table.
Angular Momentum Quantum Number	Describes the shape of a given orbital	l	0,1,2,3…,(n-1)0 for s, 1 for p, 2 for d, 3 for f, so on.	Its total count is n. Its range is from 0 to (n-1).
Magnetic Quantum Number	Determines the total number of orbitals in a sub-shell along with their orientation.	${{\text{m}}_{\text{l}}}$	-l,…,-1,0,1,2,…l	It has total (2l+1) orbitals.
Spin Quantum Number	Gives the direction of spinning of electrons. Either clockwise or anti-clockwise.	${{\text{m}}_{\text{s}}}$	$+{}^{1}/{}_{2}\text{ },\text{ }-{}^{1}/{}_{2}$	It has fixed values and that is also only two values.

Let us now solve this question from magnetic quantum number to principal quantum number:
Step (1)- We have the given value, the value of l will be 4. As, g orbital stands for l=4.
Step (2)- The total number of orbitals will be (2l+1) orbitals. We have l=4, the total orbitals will be $\left( 2\times 4+1 \right)$ or 9 orbitals.
Step (3)- We know that each orbital has only two electrons present in it. So, these 9 types of orbitals will have $2\times 9$ or 18 electrons.
Step (4)- The value of l=4, then n=5, because the range of l is from 0 to (n-1).

The correct answers of this question are options ‘a’, ‘b’ and ‘c’. g orbital is possible if n=5, l=4, it will have 18 electrons and it will have 9 types of orbitals.

Note: The common mistake committed here by the students is not taking the number of electrons inside an orbital to be two (2). There is no g-orbital in the periodic table. The greater the value of l, more will be orbitals and electrons present in it. The direct formula of the number of electrons to find from ‘l’. The formula is $2\times$ (2l+1) electrons.