Electronegativity, Bonding, Molecular Shape & Intermolecular Forces

Vocabulary flashcards covering electronegativity, bond types, molecular geometry concepts, and intermolecular forces drawn from the lecture notes.

Electronegativity (EN)

Ability of an atom to attract shared electrons toward itself in a chemical bond; increases across a period and up a group.

Valence Electrons

Outer-shell electrons that are involved in forming chemical bonds.

Noble Gases

Elements in Group 18 with full valence shells; chemically stable and generally non-reactive (e.g., He, Ne, Ar).

Covalent Bond

Chemical bond in which two atoms share valence electrons.

Ionic Bond

Bond formed by complete transfer of electrons; typically occurs when ΔEN > 1.7.

Polar Covalent Bond

Covalent bond with unequal electron sharing due to different electronegativities (ΔEN ≈ 0.4–1.7).

Nonpolar Covalent Bond

Covalent bond with equal electron sharing; usually between identical atoms (ΔEN < 0.4).

Bond Polarity

Extent to which electron density is unequally shared in a covalent bond, determined by electronegativity difference.

Electronegativity Difference (ΔEN)

Numerical difference in electronegativity between two bonded atoms used to predict bond type and polarity.

Dipole

Molecule or bond possessing two partial charges (δ+ and δ–) at opposite ends.

Miscibility

Property of two liquids to mix in all proportions forming a single phase.

Miscible

Liquids that mix completely with one another.

Immiscible

Liquids that do not mix to form a single phase.

Valence-Shell Electron-Pair Repulsion (VSEPR) Model

Theory that predicts molecular geometry by assuming electron pairs repel and arrange to minimize repulsion.

Lewis Structure

Diagram showing arrangement of atoms, bonds, and lone-pair electrons in a molecule.

Lone Pair

Pair of valence electrons on an atom that is not involved in bonding.

Intramolecular Forces

Forces that hold atoms together within a molecule or ionic lattice.

Intermolecular Forces (IMF)

Forces of attraction or repulsion between separate molecules or ions.

Strong IMF

Intermolecular attractions that give substances high melting/boiling points (typical of many liquids and solids).

Weak IMF

Relatively small intermolecular attractions leading to low melting/boiling points (typical of gases).

Gas (State of Matter)

Has neither definite shape nor volume; highly compressible and flows easily.

Liquid (State of Matter)

Has definite volume but takes shape of container; very low compressibility; flows moderately.

Solid (State of Matter)

Has definite shape and volume; virtually incompressible; does not flow.

Octet Rule / Electronic Stability

Tendency of atoms to achieve a valence shell with eight electrons, leading to chemical stability.

Central Atom (in VSEPR)

Atom of lowest electronegativity around which other atoms are arranged in a molecule.