# What are the four quantum numbers in chemistry?

##### 1 Answer

#### Explanation:

Electrons can be described by

The first quantum number is called the **principal quantum number**, and it's denoted by the letter

The second quantum number is called the **orbital angular momentum number**, and it's denoted by the letter

It represents the number of angular nodes (shown in the first image below) in an orbital, which means that it effectively represents the *shape of the orbital.*

The maximum value of

The third quantum number is called the **magnetic quantum number**, and it's denoted by

Our fourth quantum number is the **electron spin number**. It is denoted by

Essentially, every electron has a spin. This a spin is either in the direction of "up" or "down," denoted by the arrows