An Alpha particle
It is called an alpha particle.
Two atoms with the same # of protons & electrons but different # of neutrons are called isotopes, which is what I assume you want. If the number of neutrons changes, and # protons increases, then there is a Beta - particle emitted. If # of protons decreases, then an alpha particle is emitted.
When a beta particle is emitted a neutron changes to a proton in the nucleus. Thus the molecule would have one more proton, so would be an isotope of nitrogen.
Beta particle
gamma radiation!
Radioactive decay; beta decay is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted
With the ejection of a beta particle (electron), there is a minute loss of mass. Electrons have very low mass. The atomic number increases though as a neutron is transformed into a proton. A antineutrino is also ejected. In a similar process, positron emission also called beta decay,- a positron is emitted and a proton is transformed into a neutron, the atomic number decreases. A neutrino is also ejected.
Usually when isotopes undergo beta decay they emit an electron, but some isotopes emit a positron instead. This depends on the relative number of neutrons to protons in the isotope which type of beta particle is emitted. An excess of neutrons leads to the emission of an electron, while an excess of protons leads to the emission of a positron.
The number of neutrons is different for each isotope.
The naturally occurring isotope of radium we encounter is radium-226. It appears in the decay chain of uranium. When radium-226 undergoes alpha decay, radon-222 is the result. The equation looks like this: 88226Ra => 24He + 86222Rn The 24He is the alpha particle, which is a helium nucleus.
Helium
When 226Rn (atomic number 86) emits an alpha particle, it produces 222Po (atomic number 84). Emission of an alpha particle means the atom is losing two protons and two neutrons. This reduces the atomic number by two (the number of protons), and reduces the atomic mass by 4 (the number of protons plus the number of neutrons). So the number of the isotope is reduced by 4.