Quantum Numbers Part Two

Magnetic Describes the orientation of the subshell on the x, y, and z axis A specific orientation of a subshell is called an orbit The magnetic quantum number tells us which orbit the electron is in within the subshell Represented by mℓ

Hund’s Rule Electrons will spread out to all the possible orbits within a subshell before they double up.

Spin Describes the spin of the electron within the specific orbit Represented by ms Pauli exclusion principle: There can only be two electrons per orbit and they must spin in opposite directions ms = +1/2 or -1/2

How we show the quantum numbers We illustrate an element’s quantum numbers using electron configurations. Examples: Hydrogen: 1s Helium: 1s Lithium: 1s 2s Neon: 1s 2s 2p 1 2 2 1 2 2 6

1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f

Easy Trick! Gold: 79e 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 2 2 6 2 6 2 10 6 2 10 6 2 14 9

Orbital Diagrams Another method used to illustrate an element’s quantum numbers is orbital diagrams: Examples: Hydrogen ___ Helium ___ Lithium ___ ___ Neon ___ ___ ___ ___ ___ 1s 1s 2s 1s 2s 2p