Chemical Bonding Fundamentals

A set of vocabulary flashcards that summarises essential terms and definitions related to valence electrons, periodic trends, types of chemical bonds, and intermolecular forces from the lecture notes.

Chemical Bond

An interaction that holds atoms together in molecules, ions, or compounds through sharing or transferring valence electrons.

Valence Electrons

Electrons in the outermost shell of an atom; they participate in chemical bonding.

Octet Rule

Principle stating that atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell, like noble gases.

Group Number (Main-Group Elements)

Indicates the number of valence electrons; e.g., Group IV elements have 4 valence electrons.

Exception to the Octet Rule

Situations where atoms do not achieve eight valence electrons due to odd numbers, too few/too many electrons, or involvement of d-orbitals.

Lewis Symbol

Notation showing an element’s symbol surrounded by dots that represent its valence electrons.

Electronegativity (EN)

Measure of an atom’s ability to attract shared electrons in a chemical bond.

Electron Affinity (EA)

Energy released when a gaseous atom gains an electron to form an anion.

Ionisation Energy (IE)

Energy required to remove an electron from a gaseous atom, producing a cation.

Relationship of IE and EN

Elements with higher first ionisation energy generally exhibit higher electronegativity.

Cation

Positively charged ion formed when an atom loses one or more electrons.

Anion

Negatively charged ion formed when an atom gains one or more electrons.

Ionic Bond

Bond formed by electrostatic attraction between cations and anions after electron transfer, typically between metals and non-metals.

Covalent Bond

Bond formed when two non-metal atoms share pairs of valence electrons.

Metallic Bond

Attraction between metal cations and a sea of delocalised electrons within a metal lattice.

Intermolecular Forces

Weak attractions between separate molecules, including hydrogen bonding and various van der Waals forces.

Hydrogen Bond

Strong dipole-dipole attraction involving H attached to F, O, or N interacting with a lone pair on another electronegative atom.

Dipole-Dipole Interaction

Attraction between the positive end of one polar molecule and the negative end of another polar molecule.

Ion-Dipole Interaction

Attraction between an ion and the partial charges of a polar molecule.

London Dispersion Forces

Weak, temporary attractions arising from instantaneous dipoles in atoms or molecules; present in all substances, dominant in non-polar ones.