Glossary
- abundance
How much is available of substance. - atom
The smallest part of an element that can exist. - atomic number
The number of protons in the nucleus of an atom. Also called the proton number. - charge (electrical)
An imbalance of electrons and protons in a material. An excess of electrons results in negative charge, a deficit of electrons results in positive charge. - electron
Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. - element
A substance made of one type of atom only. - isotope
Atoms of an element with the same number of protons and electrons but different numbers of neutrons. - mass
The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g). - mass number
The number of protons and neutrons found in the nucleus of an atom. - neutral atom
An atom in which the number of protons and electrons is the same. - neutron
Uncharged subatomic particle, with a mass of 1 relative to a proton. The relative charge of a neutron is 0. - nuclei
Nuclei is the plural of nucleus. The nucleus is the central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. - nucleus
The central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. The plural of nucleus is nuclei. - particle
A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules. - properties
The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point. - proton
Subatomic particle with a positive charge and a relative mass of 1. The relative charge of a proton is +1. - relative atomic mass
The mean relative mass of the atoms of the different isotopes in an element. It is the number of times heavier an atom is than one-twelfth of a carbon-12 atom. - relative mass
The relative mass is the number of times heavier a particle is, compared to another. - subatomic particle
Objects found in atoms, including protons, neutrons and electrons
