Principle quantum number

[Clara Cho 2K]

How do you determine the principle quantum number of the state an electron is excited to?

[Jordan Young 2J]

The principle quantum number is which shell the electron is in. This is determined by which period the electron of the atom is in. Period 1 has a quantum number of 1, period 2 has a quantum number of 2, etc. For example, an electron is the 2s shell has a principle quantum number of 2.

[Rebecca Remple 1C]

Hi Clara,

If you are given enough information, you can do this using the Rydberg formula. You can find this formula on the constants and equations sheets. This will work if you known one of the principle quantum numbers (e.g. at ground state, Hydrogen's principle quantum number = 1). You can then plug these into the equation to get the final principle quantum number that the electron was excited to! I hope this helps :)

-Rebecca