Nuclear fission is where a heavy atom spontaneously decays to two or more lighter elements. All reactions, whether chemical or nuclear, conserve mass, charge and energy. These rules are used to balance nuclear reactions. Finally, it is necessary to multiply the first two reactions by 2 and add them together to arrive at the overall reaction. Here are some examples of other fusion reactions.
Fission reactions result in formation of lighter atoms.
The three most common decay schemes for radioactivity are beta particle emission, alpha particle emission, and gamma ray emission. Beta particle emission is when a neutron in the nucleus becomes a proton by releasing its negative charge as a high-energy electron. The atomic number of the atom that decayed by beta emission is increased by one unit when this occurs, but the atomic mass stays the same. An example of beta emission is tritium decay. The half-life for this process is 12.5 years, which means that it takes 12.5 years for any quantity of tritium to decay to half its original amount.