Radioactive decay Nuclear Decay

Alpha decay is a type of radioactive decay in which anatomic nucleus emits an alpha particle, and thereby transforms (or 'decays') into an atom with a mass number 4 less and atomic number 2 less. For example:

23892U

→

23490Th

+

42He2+ [1]

Or:

23892U

→

23490Th

+

42He

as some believe electrons are gained from the environment.