# What causes nuclear decay?

Mar 22, 2018

Unstable nuclei

#### Explanation:

Unstable nuclei cause nuclear decay. When an atom has too many protons or neutrons compared to the other, it will decay by two types, alpha and beta, depending on the case.

If the atom is light-weight and has not too many protons and neutrons, it is likely to undergo beta decay.

If the atom is heavy, like the superheavy elements (element $111 , 112 , \ldots$), they are likely to undergo alpha decay to remove both protons and neutrons.

In alpha decay, a nucleus emits out an alpha particle, or a helium-$4$ nucleus, which decreases its mass number by $4$ and proton number by $2$.

There are two types of beta decay, beta-plus and beta-minus. In beta-minus decay, an atom converts one of its neutrons into a proton, while releasing an electron $\left({e}^{-}\right)$ and an antineutrino $\left(\overline{v}\right)$.

In beta-plus decay, an atom converts one of its protons into a neutron, while releasing a positron $\left({e}^{+}\right)$ and a neutrino $\left(v\right)$ in the process.