Explanation: In γ -decay the nucleus changes its state from high to low energy through emission of electromagnetic radiation. Neither atomic number nor mass number change in a γ -decay.

Beta decay A beta particle forms when a neutron changes into a proton and a high-energy electron . When a nucleus emits a beta particle, these changes happen: the mass number stays the same. the atomic number increases by 1.

The mass number decreases by 4, and the atomic number decreases by 2. Gamma decay is the emission of a photon from the nucleus of the atom and since gamma rays are electromagnetic waves, they are pure energy, and have no mass or atomic number.

The atomic mass number does not change because a beta particle has a much smaller mass than the atom. The atomic number goes up because a neutron has turned into an extra proton. However, in beta decay, a fast moving electron is fired out of the nucleus.

In gamma decay, depicted in Fig. 3-6, a nucleus changes from a higher energy state to a lower energy state through the emission of electromagnetic radiation (photons). The number of protons (and neutrons) in the nucleus does not change in this process, so the parent and daughter atoms are the same chemical element.

Gamma rays are a radiation hazard for the entire body. They can easily penetrate barriers that can stop alpha and beta particles, such as skin and clothing. Gamma rays have so much penetrating power that several inches of a dense material like lead, or even a few feet of concrete may be required to stop them.