Chemical Bonding and Intermolecular Forces

These vocabulary flashcards define key terms related to atomic bonding, structures of matter, and intermolecular forces based on the chemistry lecture notes.

Intramolecular bond

A force that holds the atoms or ions in a compound together.

Valency

The unpaired electrons in the last shell used in chemical bonding.

Covalent bond

The sharing of at least one pair of electrons by two non-metal atoms.

Single bond

A bond formed when only one pair of electrons is being shared between atoms.

Molecule

A group of atoms held together by covalent bonds.

Diatomic elements

Elements made up of molecules containing two atoms, such as $H_2$, $N_2$, or $O_2$.

Double bond

A bond formed when there are two pairs of electrons being shared between atoms; represented as $O=O$.

Triple bond

A bond formed when there are three pairs of electrons being shared between atoms; represented as $N \text{ ≡ } N$.

Ionic bond

A transfer of electrons from a metal to a non-metal and subsequent electrostatic attraction between oppositely charged ions.

Metallic bond

The force of attraction between the free-moving (delocalised) electrons and positive metal ions.

Allotrope

A different form of an element, such as diamond and graphite for carbon.

Electronegativity

A measure of the tendency of an atom to attract a bonding pair of electrons.

Polarity

The uneven distribution of the electron cloud within a molecule caused by a difference in electronegativity.

Polar molecules

Molecules where two atoms do not share electrons equally in a covalent bond, resulting in a dipole where part of the molecule carries a slight positive charge ($\text{δ}^+$) and the other a slight negative charge ($\text{δ}^-$).

Non-polar molecules

Molecules where atoms share electrons equally in a covalent bond, resulting in no net electrical charge across the molecule.

Intermolecular force

A weak force of attraction between molecules, ions, or atoms.

London forces

The weakest intermolecular force, also known as induced dipole-induced dipole attraction, which is a temporary attractive force resulting when electrons in adjacent atoms repel each other to form temporary dipoles.

Dipole-dipole forces

Attractive forces between the positive end of one polar molecule and the negative end of another polar molecule (permanent dipoles).

Hydrogen bond

A special type of dipole-dipole attraction where a hydrogen atom is covalently bonded to a very electronegative atom ($N$, $O$, or $F$) which must also possess at least one lone pair of electrons.

Ion-dipole force

An attractive force that results from the electrostatic attraction between an ion and a neutral molecule that has a dipole.

Ion-induced dipole forces

Forces existing between ions and non-polar molecules where an ion induces a dipole in the non-polar molecule.

Dipole-induced dipole forces

Forces existing between a polar molecule and a non-polar molecule.