Neutron

Electrons are the subatomic particles that have the least mass. Neutrons and protons are found together in the nucleus of the atom.

Here the alpha particle (24He) is most massive because it has two protons and two neutrons so its mass four times of proton and neutron. A neutron and a proton have more mass than a electron. The mass of beta particle has same thing as electron.

The majority of the mass of the atom is found in the nucleus, which is made up of protons and neutrons. The part of the atom with the smallest mass is the electron.

Neutron decay is a type of radioactive decay of nuclei containing excess neutrons (especially fission products), in which a neutron is simply ejected from the nucleus. Radiation Dosimetry. Example: Proton and Neutron Decay.

Neutrons are stable inside atoms, but on their own they decay in about 15 minutes, more or less, into a few other particles. Another, called the beam method, is to produce a tightly confined spray, or beam, of neutrons and surround it with a “proton trap” to count the protons created when neutrons decay.

Nuclei are made up of protons and neutrons. While neutrons are stable inside many nuclei, free neutrons decay with a lifetime of about 15 minutes. The neutron decays into a proton, an electron, and an antineutrino of the electron type.

[+] To the best of our understanding, the proton is a truly stable particle, and has never been observed to decay. Because of the various conservation laws of particle physics, a proton can only decay into lighter particles than itself. It cannot decay into a neutron or any other combination of three quarks.

It is impossible to predict when an individual radioactive atom will decay. The half-life of a certain type of atom does not describe the exact amount of time that every single atom experiences before decaying. According to relativity, time itself can be slowed down.