Beta decay

Question 1

What happens in beta-minus decay?

Answer 1

In B- decay, a neutron in the nucleus of an unstable atom decays to become a proton and an electron. The proton stays within the nucleus, but the electron, which is the B- particle, is emmited from the nucleus at high speed as a fast-moving electron. The mass number does not change, but the atomic number increases by 1.

Question 2

What happens in beta-plus decay?

Answer 2

In B+ decay, a proton in the nucleus decays to become a neutron and a positron. The neutron stays in the nucleus. The positron, which is the B+ particle, is emitted from the nucleus at a very high speed, carrying away a positive charge and a very small amount of the nuclear mass. The mass number does not change, but the atomic number decreases by 1.

Question 3

What is a use of beta decay?

Answer 3

Carbon-14 is an unstable isotope of carbon and emits B- particles - it has a half-life of over 5700 years. This means that it can be used for radiocarbon dating, which involves finding the ages of materials that are thousands of years old. Positions can be used in hospitals to form images of patients by the use of PET scans.