Glossary Of Terms

The atomic number is the number of protons in the nucleus of an atom.

The mass number is the total number of protons and neutrons in the nucleus of an atom.

Isotopes are atoms with the same number of protons but a different number of neutrons.(same element but different mass number)

A cation is a positive ion.

An anion is a negative ion.

A compound is a substance formed when two or more elements are chemically combined.

An ionic bond is the attraction between oppositely charged ions.

A covalent bond is formed by a shared pair of electrons.

Diatomic means that there are two atoms covalently bonded in a molecule.

Metallic bonding is the attraction between delocalised electrons and positive ions in a metallic lattice.

Malleable means can be hammered into shape.

Ductile means can be drawn out into wires.

An alloy is a mixture of two or more elements, at least one of which is a metal, and the resulting mixture has metallic properties.

A nanometre is 10^-9 m.

A nanoparticle is a structure that is 1 - 100 nm in size.

Allotropes are different forms of the same element in the same physical state.

An element is a substance that consists of only one type of atom and cannot be broken down into anything simpler by chemical means.

A molecule is a particle that consists of two or more atoms chemically bonded together.

A period is a horizontal row in the Periodic Table.

A group is a vertical column in the Periodic Table.

The relative atomic mass is the mass of the atom compared with that of the carbon-12 isotope, which has a mass of exactly 12, and is the weighted mean of the mass numbers.

Percentage yield = (actual yield / theoretical yield) × 100

Water of crystallisation is water that is chemically bonded into the crystal structure.

Hydrated means that solid crystals contain water of crystallisation.