Neutrons
A Neutron is a sub atomic particle with no charge and an atomic weight of 1.67x10^-17 Kg. They are important in the nucleus as they bind to the protons by the strong force. However free neutrons, produced in nuclear fission and nuclear fusion, are unstable and undergo Beta decay. Those produced in nuclear fission perpetuate the nuclear chain reaction. Neutrons are hadrons consisting of an up quark and two down quarks. It's anti-particle is the antineutron.