Changing the temperature of atoms affects their chemical reaction rate, but has no effect on their rate of radioactive decay. Why is one rate affected, but not the other?

Temperature is the average vibrational kinetic energy of the molecules. As the temperature increases, the atoms gain more kinetic energy so that they move faster and collide frequently with other atoms. According to kinetic theory, the collision is responsible for the chemical reaction so that increasing temperature results in more collisions which leads to increased rate of chemical reaction.

Radioactive decay is the result of variations in the nuclear and electroweak forces inside the nucleus of an atom. Changing the temperature affects the atom only as a whole and the external conditions of the atoms do not affect the forces inside the nucleus. As a result temperature has no effect in the rate of radioactive decay.