-rays have their origin in the nucleus.
This view of the origin of
- and
-particles explains very simply the way in which the change in the chemical properties of the radioactive substances is connected with the nature of the particles emitted. The results of experiments are expressed in the two rules[39]:—
1. Whenever an
-particle is expelled the group in the periodic system to which the resultant product belongs is two units less than that to which the parent body belongs.
2. Whenever a