Question

When a nucleus emits alpha radiation, its mass number drops by ___(digit).

Answer 1

An alpha particle is a doubly charged helium nucleus. When an alpha particle is emitted from a nucleus, the nucleus loses two protons and two neutrons. This means the mass number decreases by 4 and the atomic number decreases by 2. A new element is formed that is two places lower in the Periodic Table than the original element.