Beta decay is a type of radioactive decay in which an unstable atomic nucleus transforms into a more stable one by emitting a beta particle. There are two types of beta decay: beta-minus (β-) decay and beta-plus (β+) decay.
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Beta-minus (β-) decay: In this process, a neutron in the nucleus is converted into a proton while emitting an electron (the beta particle) and an antineutrino. This results in an increase in the atomic number by one, creating a new element. For example:
\[\text{n} \rightarrow \text{p} + e^- + \bar{\nu}_e\]
A common example is the decay of carbon-14 (^14C) into nitrogen-14 (^14N):
\[^{14}{6}\text{C} \rightarrow ^{14}{7}\text{N} + e^- + \bar{\nu}_e\]
Here, ^14C has 6 protons and 8 neutrons, and it transforms into ^14N, which has 7 protons and 7 neutrons.
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Beta-plus (β+) decay: In this process, a proton in the nucleus is converted into a neutron, emitting a positron (the beta particle) and a neutrino. The atomic number decreases by one. An example is the decay of fluorine-18 (^18F) into oxygen-18 (^18O):
\[^{18}{9}\text{F} \rightarrow ^{18}{8}\text{O} + e^+ + \nu_e\]
Here, ^18F has 9 protons and 9 neutrons, and it transforms into ^18O, which has 8 protons and 10 neutrons.
Beta decay plays a significant role in nuclear chemistry, influencing the stability of isotopes and contributing to various applications, including radiocarbon dating and medical imaging.