- Proton
- Electron
- Neutron
- Ion
The neutron is a subatomic particle with no net electric charge—it is electrically neutral. Discovered by James Chadwick in 1932, neutrons reside in the atomic nucleus alongside positively charged protons. The neutron’s neutrality allows it to approach and interact with atomic nuclei without electrostatic repulsion, making it crucial for nuclear reactions and stability. Neutrons have slightly greater mass than protons (approximately 1.67493 × 10⁻²⁷ kg vs. 1.67262 × 10⁻²⁷ kg). Within stable nuclei, neutrons help overcome proton-proton electrostatic repulsion through the strong nuclear force, contributing to nuclear cohesion. The neutron number (N) varies among isotopes of the same element—for example, carbon-12 has 6 neutrons, carbon-14 has 8, both with 6 protons. Free neutrons (outside nuclei) are unstable, decaying via beta decay into a proton, electron, and antineutrino with a half-life of about 880 seconds. Neutrons are essential in nuclear fission reactions, neutron scattering for materials research, and medical applications like boron neutron capture therapy for cancer. Understanding neutron properties is fundamental in nuclear physics, chemistry, and astrophysics.
