A radioactive element has an unstable nucleus that emits particles in the form of alpha, beta, or gamma radiation. A stable element has a nucleus that does not emit such particles
Answer:
The outermost shell of helium for example is filled with only two electrons. Hydrogen and lithium become stable by acquiring the electronic configuration of the nearest inert gas, which is helium. This is the duplet (or duet) rule.
Explanation:
