The heaviest form of radioactive decay among the options given is D. alpha decay.
Explanation:
1. Alpha decay involves the emission of an alpha particle, which consists of two protons and two neutrons bound together, equivalent to a helium-4 nucleus.
2. This decay process results in the parent atom losing two protons and two neutrons, causing it to transform into a different element located two spots to the left on the periodic table.
3. Alpha decay is characterized by relatively high mass and low penetrating power, making it one of the least penetrating forms of radiation.
4. In contrast, gamma decay (A) involves the emission of gamma rays, which are high-energy electromagnetic radiation, and is not associated with a change in the atomic number or mass of the nucleus.
5. Omega decay is not a commonly recognized form of radioactive decay, and beta decay (C) involves the emission of beta particles (electrons or positrons) from the nucleus, resulting in a change of a neutron to a proton or vice versa.
In summary, alpha decay is the heaviest form of radioactive decay among the options provided, characterized by the emission of alpha particles with high mass and low penetrating power.
