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An Electron's Address
An Electron's Address
Electron configurations show how all of the electrons in an atom are arranged, but what if we want to reference a single specific electron?
Quantum numbers allow us to talk about a specific electron within an electron configuration.
every electron has 4 quantum numbers:
Principle Quantum Number (n) - the energy level
Azimuthal (angular) Quantum Number (l) - the orbital shape; s=0, p=1, d=2, f=3
Magnetic Quantum Number (ml) - the orientation of the orbital, or "which box does it occupy"
Spin Projection Quantum Number (ms) - spin of the electron, or is the arrow up or down? up = +1/2, down = -1/2
magnetic quantum numbers are determined by orbital orientation.
Example
Example
What are the quantum numbers for the circled electron?
The principle number of that electron is 2 because it is a 2p orbital and therefore in the 2nd energy level.
The Azimuthal number is 1 because it is in a 2p orbital and all p orbitals have an azimuthal number of 1.
The magnetic number is -1 because it is one box to the left of center.
the spin number is -1/2 because the arrow is pointed down.
The quantum numbers are written in brackets as follows. {2, 1, -1, -1/2}
Practice
Practice
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