# Explain Azimuthal Quantum Number

Azimuthal Quantum Number is a type of quantum number defined for an. atomic orbital which determines its orbital angular momentum as well as also. describes the shape of the orbital of an electron within the shell. It’s denoted in $iota$. This quantum number denotes the sub-level or sub shell in a given principal energy shell to which an electron belongs. This is also called secondary quantum number. There are n possible values of $iota$ ranging from zero to one less than n for that state i e , $iota$. = 0, 1, 2. (n – 1) The relation between angular momentum of the electron as well as $iota$ isAngular Momentum = $sqrt{iota (iota +1)}$ $frac{h}{2pi}$. . where h = Plancks constant The various sub-levels or sub-shells are another designated by letters s,. p, d, f depending upon the values of $iota$ as shown below:. . . . . . . . . . . . . Value of $iota$. . 0. . 1. . . . . . . . 2. . . . . . . . 3. . . . . . . . . . . . . . . . . . Symbol of Sublevel. . . . s. p. . . . . . . d. . . . . . . f. . . . . . . . . . . Each value of $iota$ represents a particular sub-shell or sub-level. For e g. for n = 3, $iota$ can have three values, i e, $iota$ = 0,1,2. This means that there are three subshells in the third energy level. . Electrons present in an atom are described by a set of four numbers which are collectively known as quantum numbers. These are of four types:Principal Quantum number (n)Azimuthal Quantum Number ($iota$)Magnetic Quantum Number ($m_{iota}$)Spin Quantum Number (ms) Each of these quantum numbers describes a specific feature of electron. These features include size as well as shape of orbital of electron, direction of orientation as well as spin of orbital. Principal quantum number describes the size of orbital of an electron. It’s denoted by n. higher the value of n, larger is the size of orbital. value of n can never be zero Azimuthal quantum number describes the shape as well as type of orbital. It’s denoted by $iota$. Its value ranges from 0 to n – 1. Azimuthal quantum number is of 4 types: s, p, d as well as f. The shapes of orbital depend on these 4 types of azimuthal quantum numbers. Azimuthal quantum numbers were first derived from Bohr’s Atomic Model. It was postulated by Arnold Sommerfield. Let us study about the Azimuthal Quantum Number in detail. . . . . . . . . .