Atomic Structure and Ionisation Energy Flashcards

Vocabulary flashcards covering core terms, sub-atomic particles, atomic orbitals, electron configurations, and ionisation energy trends from the lecture notes.

Proton number

The number of protons present in the nucleus of an atom, represented by $Z$.

Nucleon number

The total number of protons and neutrons in the nucleus of an atom, also called the mass number ($A$).

Isotopes

Atoms of an element with the same number of protons but a different number of neutrons.

Orbital

A region around the nucleus where a maximum of $2$ electrons can be found.

s orbital

An atomic orbital that is spherical in shape.

p orbital

An atomic orbital that has a dumbbell shape.

Subshell

A set of orbitals with identical energy.

Principal quantum number ($n$)

A number specifying the energy level or shell in which electrons are arranged.

Ground state

The state of an atom or ion in which all electrons occupy the lowest available energy levels.

Excited state

The state of an atom in which electrons have absorbed energy to move to higher energy orbitals.

Free radical

A species with one or more unpaired electrons.

Electron spin

The intrinsic property of an electron to spin on its axis, where two electrons in the same orbital have opposite spins to reduce repulsion.

First ionisation energy

The amount of energy required to remove one electron from one mole of gaseous atoms to form gaseous cations.

Shielding effect

The repulsion caused by inner shell electrons that shields valence electrons from nuclear attraction.

Spin-pair repulsion

The repulsion between paired electrons in the same orbital that makes one of the electrons easier to remove compared to an unpaired electron in a singly occupied orbital.