[Photo: James Chadwick]
In physics, the neutron is a subatomic particle with
no net electric charge and a mass slightly larger than that of a proton.
The nuclei of all atoms
consist of protons and neutrons, which are therefore collectively referred to
as nucleons. The number of protons in a nucleus is the atomic number and
defines the type of element the atom forms. The number of neutrons determines
the isotope of an element. For example, the carbon-12 isotope has 6 protons and
6 neutrons, while the carbon-14 isotope has 6 protons and 8 neutrons.