Chemistry Lecture: Quantum Numbers and Electron Configuration

Practice flashcards covering key concepts on quantum numbers, electron configurations, and trends in chemistry.

Hund's Rule

Electrons will occupy degenerate orbitals singly before pairing up.

Quantum Numbers

A set of numerical values that describe the unique quantum state of an electron in an atom.

Principal Quantum Number (n)

Indicates the energy level and size of the orbital; can be any positive integer.

Azimuthal Quantum Number (l)

Indicates the shape of the orbital; possible values range from 0 to n-1.

Magnetic Quantum Number (m_l)

Indicates the orientation of the orbital; possible values range from -l to +l.

Spin Quantum Number (m_s)

Indicates the spin direction of the electron; can be +1/2 or -1/2.

Electron Configuration

The distribution of electrons in an atom's orbitals, expressed as a series of numbers and letters.

Abbreviated Electron Configuration

A shorthand method to represent electron configurations using noble gas core notation.

Effective Nuclear Charge

The net positive charge experienced by valence electrons after accounting for shielding from core electrons.

Ionization Energy

The energy required to remove an electron from a gaseous atom or ion.

Electron Affinity

The amount of energy released when an electron is added to a neutral atom to form a negative ion.

Electronegativity

A measure of the tendency of an atom to attract a bonding pair of electrons.

Paramagnetic

Describes a species that has unpaired electrons and is attracted by a magnetic field.

Diamagnetic

Describes a species that has all paired electrons and is not attracted to a magnetic field.

Size Trends in the Periodic Table

Atoms decrease in size across a period and increase in size down a group due to changes in electron shielding and effective nuclear charge.

Transition Metals

Elements found in Groups 3-12 of the periodic table, typically characterized by d-electron involvement in bonding and variable oxidation states.