## What's the difference between a shell, a subshell, an energy level, and an orbital?

Elizabeth Johnson 1I
Posts: 53
Joined: Wed Sep 11, 2019 12:16 am

### What's the difference between a shell, a subshell, an energy level, and an orbital?

I'm a little confused as to if some of these words are interchangeable or not. If you guys could define them and their differences from one another that would be amazing.

zoedfinch1K
Posts: 57
Joined: Thu Jul 25, 2019 12:16 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

Shell: the area that an electron can be found; think of it as the electron "cloud". This would be the quantum number n.
Subshell: this is the shape of a specific shell (s, p, d, f) and is the quantum number l.
Orbital: the specific orientation of the different subshells.

Here's a graphic that helps:
Attachments  Ryan 1K
Posts: 101
Joined: Fri Aug 09, 2019 12:15 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

The three quantum numbers (n, l, and ml) describe an orbital, which is the math function used to describe an electron's probable position.

The principle quantum number (n) refers to the overall energy and size of the orbital. An energy shell and energy level are interchangeable terms.

The angular momentum quantum number (l) refers to the shape of the orbital. For example, the s subshell is a sphere, and the p subshell is dumbell-shaped.

The magnetic quantum number (ml) refers to the specific orbital that belongs in a subshell. For example, there are three orbitals that can exist in a p subshell. Depending on the orientation of the orbital, the ml can be aligned in along the x plane (px), the y plane (py), and the z plane (pz).

Once again, all three quantum numbers describe different aspects of an orbital.

zoedfinch1K
Posts: 57
Joined: Thu Jul 25, 2019 12:16 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

Also, I believe energy levels and shells refer to the same thing.

Lauren Stack 1C
Posts: 100
Joined: Sat Aug 17, 2019 12:18 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

A shell is defined by n, which can be whole number values (1, 2, 3, etc).
The term subshell refers to the l (s, p, d, f) and the shapes that are made by the expected/potential location of the electron.
An orbital is a combination/description of all of the quantum numbers (which are n, l, ml, and ms) to provide a complete explanation of the energy level of the electron being described.
An energy level is just the specific amount of energy that an electron has acquired and is commonly associated with a shell number.

Siya Shah 1J
Posts: 50
Joined: Sat Aug 17, 2019 12:15 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

The Principle Quantum Number (n) refers to the subshell. The orbital angular momentum quantum number l determines the shape of the orbital and the magnetic quantum number m(l) indicates how many orbitals there are in the subshell. Energy level is just a broader term for subshell.

Ruth Glauber 1C
Posts: 100
Joined: Wed Sep 18, 2019 12:20 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

Shell is the quantum number n. Subshell is the shape (s, p, d, f) and quantum number l. Orbital is the orientation of the subshell!

Elizabeth Johnson 1I
Posts: 53
Joined: Wed Sep 11, 2019 12:16 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

Thank you all so much for replying! This clears so much up! :) Chem community pullin thru

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

### Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

Just to add on, a hydrogen atom (or any single electron atom), has s,p, and d orbitals that are degenerate. This means they all have equal energy level because there are no electrons interacting with each other.