Beta-Minus Decay
- Beta (β−) particles are high energy electrons emitted from the nucleus
- β− particles are emitted by nuclei that have too many neutrons
- During beta decay, a neutron changes into a proton and an electron
- The electron is emitted and the proton remains in the nucleus
- A completely new element is formed because the atomic number changes
Beta-minus decay often happens in unstable nuclei that have too many neutrons. The mass number stays the same, but the atomic number increases by one
- An electron has a mass number of 0
- This is because electrons have a negligible mass, compared to neutrons and protons
- Therefore, the mass number of the decaying nuclei remains the same
- Electrons have an atomic number of -1
- This means that the new nuclei will increase its atomic number by 1 in order to maintain the overall atomic number before and after the decay
- The following equation shows carbon-14 undergoing beta decay
- It forms nitrogen-14 and a beta minus particle
- Beta minus particles are written as an electron in this equation
The carbon nucleus emits a beta particle, causing its charge to increase. This means it changes into a new element