Discovery of neutron

• Neutron was discovered by James Chadwick in 1932.
• The reason for the late discovery of neutrons was its neutral nature.

• Chadwick bombarded a thin foil of beryllium with fast moving α-particles and observed that electrically neutral particles having mass slightly greater than that of protons were emitted.

₄Be⁹ + ₂He⁴ → ₆C¹² + ₀n¹

• These neutral particles were called neutrons
• It is a fundamental particle of atom present in all the atoms except hydrogen or protium.

Neutron is unstable it decays as:

₀n¹ → ₁p¹ + _–1e⁰ + ₀e⁰_{(antineutrino)}

• Specific charge of a neutron is zero.

Characteristics of a Neutron:

1. Mass of a Neutron:

• Relative Mass of a neutron is 1 u.
• Mass of a neutron is 1.675 × 10^–27 kg.

2. Charge of a Neutron:

• Neutron has no charge.
• It is electrically neutral.