## Quantum number m

Johnathan Smith 1D
Posts: 108
Joined: Wed Sep 11, 2019 12:16 am

### Quantum number m

I know we’re past quantum numbers but can someone explain to me what quantum number m tells us and how we are able to know its value.

Naji Sarsam 1F
Posts: 104
Joined: Sat Aug 17, 2019 12:18 am

### Re: Quantum number m

There are four quantum numbers: n, l, $m_{l}$, and $m_{s}$

These four quantum numbers explain the individual properties of every electron possible in an atom. Moreover, in one atom, two electrons cannot have the same values for all four quantum numbers.

Pertaining to the quantum number "m", there are two: $m_{l}$ and $m_{s}$
$m_{l}$:
"the magnetic quantum number"
it determines which orientation of the orbital the electron resides--for example if it resides in $p_{x}$, $p_{y}$, or $p_{z}$
The possible values for $m_{l}$ are any integer number starting with the value of the quantum number l until the value of -l

$m_{s}$:
"the spin magnetic quantum number"
it determines whether the spin of an electron is "spin up" or "spin down"
What's important to understand about spin is not that the electron is literally spinning. Rather that when two electrons are in the same orbital, they cannot both be spin up or spin down. One must be spin up and the other spin down.
The possible values for $m_{s}$ are either +1/2 for spin up, or -1/2 for spin down

Jasmine Summers 4G
Posts: 50
Joined: Wed Sep 18, 2019 12:17 am

### Re: Quantum number m

The quantum number m refers to the magnetism of an electron, and for m,s it refers to its spin. An electrons can either be +1/2 or -1/2, meaning it spins up or down. Paired electrons always have opposite spins.

PGao_1B
Posts: 50
Joined: Sat Jul 20, 2019 12:15 am

### Re: Quantum number m

The magnetic quantum number ml determines the number of orbitals and their orientation within a subshell. Consequently, its value depends on the orbital angular momentum quantum number l. Given a certain l, ml is an interval ranging from –l to +l, so it can be zero, a negative integer, or a positive integer.

Unlike n, l, and ml, the electron spin quantum number ms does not depend on another quantum number. It designates the direction of the electron spin and may have a spin of $+\frac{1}{2}$ or $-\frac{1}{2}$. This means that when ms is positive the electron has an upward spin, which can be referred to as "spin - up." When it is negative, the electron has a downward spin, so it is "spin - down." The significance of the electron spin quantum number is its determination of an atom's ability to generate a magnetic field or not.