Sometimes, when a nucleus can become more stable by increasing its neutron-
to-proton ratio, it takes a proton and converts it to a neutron. The result of this is
that the atomic number decreases by 1, and the mass number remains the same;
this type of radioactive decay is known as positron emission. When a nucleus
undergoes positron emission, it emits a positron. What is a positron? Well, it’s a
positively charged particle, but it isn’t a proton. It has the same mass as an
electron, but it carries a positive charge. A positron is symbolized as .
To sum up positron emission:• A proton is converted to a neutron.• A positron is emitted.• The atomic number decreases by 1, and mass number stays the
same.Radioactive Decay Type 4: Gamma Decay
We should also mention gamma rays, which are a form of electromagnetic
radiation. Radioactive nuclei often emit gamma rays; these are high-energy
particles with the symbol , together with alpha particles, beta particles, or
positrons. When nuclei emit alpha or beta particles, they are sometimes left in a
high-energy state, but when they emit gamma rays, they become stable.
Summary of Radioactive (or Nuclear) Decay