## Orbitals vs. subshells; Quantum numbers

Catherine Lowe 1B
Posts: 22
Joined: Fri Sep 25, 2015 3:00 am

### Orbitals vs. subshells; Quantum numbers

What exactly is the difference between atomic orbitals and subshells? Also, I am getting a little confused regarding what each quantum number represents. Could someone please explain the differences between the 4 quantum numbers? Thank you.

Matthew Gutierrez 2D
Posts: 19
Joined: Fri Sep 25, 2015 3:00 am

### Re: Orbitals vs. subshells; Quantum numbers

Think of a set of the numbers as an address. For example you could look at a set of quantum numbers (n,l,ml,ms) as (country, housing complex, room, 1/2 or -1/2). It's not a literal analogy, but it helps.

n= energy level and size (1,2,3,etc.)

Within each energy level there are:

l= shape of the orbital, the shape of the "house"
0 is an s orbital shape
1 is a p orbital shape
2 is a d shape

ml= subshells or the "rooms" inside that particular orbital shape; the orientation (x,y,z, etc.)
They have values of l, l-1, -l
So, for example, a p-orbital with l=1 has subshells/"rooms labelled -1, 0, 1, so it has 3 subshells/rooms

ms= spin
Either 1/2 or -1/2

Each electron has its own set of unique quantum numbers. According to the Pauli Exclusion principle, no two electrons may have the exact same set of quantum numbers.

So, whenever you think of quantum numbers, think "where does this electron live"? Oh, it lives in n=2, l=1, ml=-1, and ms=1/2. This corresponds to a 2px orbital. No other electron may have this exact same set of numbers. So its "neighbor" would have n=2, l=1, ml=-1, and ms=-1/2.

Sorry if anything is unclear or if I have made a mistake.

Good luck! :)