14.4 Bonding in Organic Molecules – Sigma Bonds and Carbon sp³ Hybridisation

Vocabulary flashcards covering sigma bonds, carbon’s electron configuration, sp³ hybridisation, tetrahedral geometry, and related concepts from the lecture.

Sigma (σ) bond

A single covalent bond formed by direct overlap of atomic orbitals, with the shared electron pair located between the nuclei of the bonded atoms.

Carbon electronic configuration

1s² 2s² 2p²; gives carbon four valence electrons available for covalent bonding.

Valence electrons in carbon

The four outer-shell electrons that allow carbon to form up to four covalent bonds to achieve a noble-gas configuration.

Tetrahedral arrangement

The three-dimensional orientation adopted by four bonding pairs around a central atom, maximizing separation and giving bond angles of 109.5°.

109.5° bond angle

Characteristic angle between σ bonds in a tetrahedral geometry, as found in sp³-hybridised carbon atoms.

sp³ hybridisation

Mixing of one s and three p orbitals in carbon to create four equivalent hybrid orbitals that arrange tetrahedrally and form σ bonds.

Ethane (C₂H₆) molecular shape

Two sp³-hybridised carbons each bonded tetrahedrally to three hydrogens and the other carbon, giving all bond angles close to 109.5°.

Electrostatic attraction in covalent bond

Force between the negatively charged shared electron pair and the positively charged nuclei that holds two atoms together in a σ bond.

Noble-gas configuration of neon

Stable electron arrangement (1s² 2s² 2p⁶) that carbon attains by forming four σ bonds.

Bonding-pair repulsion

Tendency of regions of negative charge (bonding electron pairs) to position as far apart as possible, determining molecular geometry such as tetrahedral in carbon.