Lecture 5_9-2-25 Electron Configurations, Magnetic Properties, Valence File

Flashcards covering electron configurations, quantum numbers, magnetic properties, and related rules from Lecture 5.

Principal Quantum Number (n)

Describes orbital energy and size; corresponds to the period on the Periodic Table; numerical restrictions are 1, 2, 3, etc.

Angular Momentum Quantum Number ("ell" or "")

Describes orbital energy shape and the number of nodal planes; corresponds to s, p, d, f blocks on the Periodic Table; numerical restrictions from 0 up to (n-1).

Magnetic Quantum Number (m)

Describes orbital orientation and the number of orbitals in a given sublevel; corresponds to block size; numerical restrictions are integer values from -"ell" to 0 to +"ell".

Spin Quantum Number (ms)

Describes electron spin; numerical restrictions are +1/2 or -1/2.

Energy of Sublevels Rule

Energy increases with (n + "ell"); if two sublevels have the same (n + "ell"), the higher n has the higher energy.

Electron Configuration Notation

A shorthand method (nl#) to represent the distribution of electrons in atomic orbitals, where 'n' is the principal quantum number, 'l' is the angular momentum quantum number (represented by a letter like s, p, d, f), and '#' is the number of electrons in that sublevel.

Pauli Exclusion Principle

States that no two electrons in the same atom can have the same set of four quantum numbers (n, "ell", m"ell", ms).

Hund's Rule

Within a sublevel, the lowest energy electron configuration is obtained when the number of electrons with the same spin is maximized (orbitals are filled singly before pairing).

Ground State

The lowest possible energy state of an atom's electron configuration.

Excited State

An electron configuration where an electron has moved to a higher energy orbital, which requires input of additional energy.

Paramagnetic Atom

An atom that has one or more unpaired electrons and will respond to an external magnetic field.

Diamagnetic Atom

An atom that has no unpaired electrons and will not respond to an external magnetic field.

Chromium (Cr) Electron Configuration Exception

The ground state electron configuration is [Ar]4s13d5, an exception to fully filling 4s before adding electrons to 3d.