Chemistry Definitions Module 2.2

The average energy required to break a bond. Measures the strength of a covalent bond. Measured using a variety of molecules with a specific bond

A pair of outer-shell electrons involved in bonding

A strong bond formed between two atoms due to strong electrostatic forces between a shared pair of electrons and the atomic nuclei.

A covalent bond in which both electrons in the shared pair are from the same atom

The ability of an atom to attract bonding electrons in a covalent bond. Quantified using Pauling’s electronegativity values. Increases towards F in the periodic table.

Pairs of electrons around a nuclei repel each other so that in the shape of the molecule the pairs of electrons are positioned as far apart as possible. Lone pairs repel more than bonded pairs as they are closer to the nucleus of the central atom.

Interactions between dipoles of different molecules

Intermolecular bonding between molecules containing N/O/F and H. The lone pair on the N/O/F allows for the hydrogen.

Electrostatic attraction between positive and negative ions

Compounds made of oppositely charged ions. High melting and boiling points. Only conducts electricity when molten or aqueous. Generally soluble

A giant structure in which oppositely charged ions are strongly attracted in all directions

The shape of a molecule where the central atom has 2 bonding pairs

Instantaneous dipole induced dipole interactions caused when the random movement of electrons creates a temporary dipole in one molecule. This induces a dipole in a neighbouring molecule.

A pair of outer-shell electrons not involved in bonding

Properties of a bulk material rather than the individual atoms / molecules that make up the materials

The shape of an atom where the central atom has 2 bonding pairs and 2 lone pars

The shape of a molecule in which the central atom has 6 pairs of bonded electrons

A permanent uneven distribution of charge

A covalent bond that has a permanent dipole due to different electronegativities of atoms that make up the bond

Molecule that contains polar bonds with dipoles. Is unsymmetrical so that dipoles don’t cancel out

The shape of a molecule which has 3 bonded pairs and 1 lone pair

A solid structure made up of covalently bonded molecules attracted by intermolecular forces. Generally have low melting and boiling points. Usually insoluble in water but soluble i organic solvents. Don’t conduct electricity

The shape of a molecule in which the central atom has 4 bonding pairs

The shape of a molecule in which the central atom has 5 bonding pairs