Definition - What does Beta Particle mean?
A Beta Particle is a subatomic particle emitted from nucleus of radioactive atoms called beta atoms. This particle is identical with an electron. The difference between an electron and a Beta Particle is that the electron originates outside the nucleus while the Beta Particle originates inside the nucleus. It is also called high-energy electron because it moves very fast. The Beta Particle is negatively charged because it is an electron and has less mass or weight than an alpha particle but more than gamma rays. It can be ejected from a nucleus when a big or a small nucleus breaks.
Petropedia explains Beta Particle
Beta Particles are emitted when the ratio of neutrons to protons in the nucleus is very high. In this case, excess amount of neutrons transforms to form electrons and protons. The protons stay in the nucleus whereas the electrons are energetically ejected. In this process the number of neutrons decreases by one while number of protons increases by one. The radionuclide gets changed to a different element with the change of neutron to proton as number of protons in nucleus of atoms determines the element. The decay of the technetium-99 that has so many neutrons to be stable can be considered as an example of beta decay. The neutrons in the nucleus get converted into protons and Beta Particles. The nucleus emits some gamma rays as well. The new atom formed holds the same mass number and the number of protons increases to 44. The atom then becomes ruthenium atom.