# What does beta decay mean?

May 3, 2016

The decay of a neutron into a proton.

#### Explanation:

$\beta$-decay is the decay of a neutron into a proton (or a proton into a neutron) with the release of an electron to conserve charge. It also releases a neutrino. This keeps the mass the same (neutrons and protons weigh about the same) but increases the atomic number by one.

$\beta$-decay happens when a nucleus has too many neutrons and is unstable.

Atomic number, $Z$, is the number of protons, and mass number $X$ is the total number of neutrons plus protons. In notation of element $A$ this is written as

""_ Z^XA

A theoretical example of $\beta$-decay using carbon-12 ($Z = 6 , X = 12$) would increase the atomic number by one to make nitrogen and keep the mass the same.

${\text{_ 6^12C->""_ 7^12N+}}_{-} {1}^{0} e$

Check this is correct by adding up the numbers on the top and bottom - they should be the same on both sides

$12 \to 12 + 0$
$6 \to 7 - 1$