Electrons in Atoms, Atomic Structure, and Chemical Bonding Flashcards

Vocabulary practice flashcards generated from lecture notes covering electron configuration, ionisation energy trends, chemical bonding types, VSEPR molecular shapes, orbital overlap, and hybridisation.

Principal Energy Levels

Main quantum shells outside the nucleus designated by n = 1, 2, 3, 4\null, containing electrons of similar distance and energy, holding a maximum of $2n^2$ electrons.

Atomic Orbital

A region of three-dimensional space around an atom's nucleus where there is a high probability of finding electrons, holding a maximum of 2 electrons.

Aufbau Principle

A rule governing electron configuration stating that electrons fill the lowest available energy levels before occupying higher ones.

Pauli Exclusion Principle

A rule stating that if two electrons occupy the same atomic orbital, they must have opposite spins.

Hund's Rule of Maximum Multiplicity

A rule stating that electrons occupy orbitals of equal energy singly with parallel spins before pairing up to minimize electron-electron repulsion.

First Ionisation Energy ($\text{IE}_1$)

The energy needed to remove one mole of electrons from one mole of gaseous atoms of an element to form one mole of gaseous $1+$ ions.

Second Ionisation Energy ($\text{IE}_2$)

The energy required to remove one mole of electrons from one mole of gaseous unipositive ($1+$) ions to form one mole of gaseous dipositive ($2+$) ions.

Nuclear Charge

The electrostatic attractive force exerted by positive protons in the nucleus on negative electrons in the energy levels.

Shielding Effect

The repulsion of outer valence electrons by full inner electron shells, reducing the effective nuclear charge felt by outer electrons.

Spin-pair Repulsion

The increased electrostatic repulsion between two electrons paired within the same atomic orbital, making them easier to remove.

Ionic Bond

The electrostatic attraction between oppositely charged ions (positively charged cations and negatively charged anions) arranged in a crystal lattice.

Coordination Number

The number of nearest-neighbor ions of opposite charge that immediately surround a specific ion within a crystal lattice.

Covalent Bond

The electrostatic attraction between the nuclei of two atoms and a shared pair of electrons.

Lone Pair

A pair of outer-shell valence electrons that is not shared with another atom or involved in chemical bonding.

Octet Rule

The chemical principle stating that atoms tend to gain, lose, or share electrons to achieve a stable outer-shell configuration of 8 electrons.

Co-ordinate Bond

A type of covalent bond (also called a dative covalent bond) where both shared electrons are provided by a single donor atom.

Valence-Shell Electron-Pair Repulsion (VSEPR) Theory

A model used to predict molecular geometry based on minimizing electrostatic repulsion between bonding and non-bonding electron pairs around a central atom.

Sigma ($\sigma$) Bond

A covalent bond formed by the direct axial (head-on or end-on) overlap of atomic orbitals, with symmetrical electron density along the internuclear axis.

Pi ($\pi$) Bond

A covalent bond formed by the sideways overlap of adjacent $p$ atomic orbitals above and below the internuclear axis.

Hybridisation

The mixing of atomic orbitals (such as $s$ and $p$) on a single atom to form new hybrid orbitals intermediate in character for bonding.

Free Radical

A neutral or charged chemical species that possesses one or more unpaired electrons.

Electronegativity

The power of an atom to attract a shared pair of electrons to itself within a covalent bond.

Bond Energy

The energy required to break one mole of a specific covalent bond in the gaseous state.

Bond Length

The internuclear distance between two covalently bonded atoms at their lowest energy position.

$s$ Orbital Shape

A spherical atomic orbital centered around the nucleus where electrons can move anywhere within the sphere.

$p$ Orbital Shape

A dumbbell- or hourglass-shaped atomic orbital with two lobes arranged along an axis ($x$, $y$, or $z$) centered at the nucleus.