Question

Azimuthal quantum number defines:
a.) e/m ratio of electron
b.) angular momentum of electron
c.) spin of electron
d.) magnetic momentum of electron

Answer 1

Hint: There are four types of quantum numbers that are assigned to the electrons in an atom. Among these four quantum numbers, the azimuthal quantum number implies the angular momentum of an atomic electron. It is also responsible for describing the shape of an orbital as well.

Complete step by step answer:
For all the atomic electrons, there are four quantum numbers: principle quantum number (n), azimuthal quantum number(l), magnetic quantum number(m), and spin quantum(s) number. These quantum numbers are utilized to describe the state of an electron or orbital properly.

Principle quantum number (n): It designates the size of the orbital and the energy level of electrons.
Azimuthal quantum number (l): It designates the angular momentum of electrons and shape of an orbital.
Magnetic quantum number (m): It designates an orbital’s spatial orientation.
Spin quantum number (s): It describes the direction of an electron’s spin (either clockwise or anti-clockwise).
Hence, azimuthal quantum number describes the angular momentum of an atomic electron and it is also known as angular momentum quantum number, designated by the symbol ‘l’.
The values of azimuthal quantum number vary from zero (0) to (n-1).
For example, the p-orbital has a value of l=1. The d-orbital has a value of l=2.
Let’s look at the answer options:
e/m ratio of an electron is called the charge to mass ratio and it is not at all associated with any of the quantum numbers. Hence, option A cannot be the correct answer.
Spin of an electron is described by the spin quantum number which tells us the direction in which a particular electron is spinning. Hence, option C cannot be the correct answer.
Magnetic momentum of an electron is the magnetic property which occurs due to spin and charge of an electron. It is not described by the azimuthal quantum number. Hence, option D cannot be the correct answer.
So, the correct answer is “Option B”.

Note:Students sometimes get confused between magnetic momentum and angular momentum of an electron while selecting an answer for azimuthal quantum number. The magnetic momentum of an electron depends upon both the charge and angular momentum of an electron. But azimuthal quantum number only describes the angular momentum of an electron. Hence, it cannot describe the magnetic momentum of an electron.