91Ó°ÊÓ

Alpha decay is a fascinating type of radioactive decay. During this process, an atomic nucleus ejects an alpha particle. What's an alpha particle, you ask? It's a tiny chunk consisting of 2 protons and 2 neutrons.
This means when a nucleus undergoes alpha decay,

• its atomic number decreases by 2 (because it loses 2 protons),
• and its mass number decreases by 4 (because it loses 2 protons and 2 neutrons, totaling 4).

After alpha decay, the original element transforms into a completely new one. An example is the decay of plutonium-239 (\({ }_{94}^{239} \mathrm{Pu}\)). By losing an alpha particle, it becomes uranium-235 (\(^{235}_{92} \mathrm{U}\)). Now the atom is no longer plutonium, but has turned into uranium!
Alpha decay is a common process for heavy elements, like plutonium, and it’s a crucial part of understanding nuclear stability.

Beta minus decay (\(\beta^-\)) is another intriguing type of radioactive decay. Here, a neutron within the nucleus is converted into a proton. This conversion involves the emission of an electron, which we commonly refer to as a beta particle, and an antineutrino.
As a result of beta minus decay,

• the mass number of the element stays the same,
• but the atomic number goes up by 1.

This increase in atomic number means the original element becomes a new one. A perfect example is sodium-24 (\({ }_{11}^{24} \mathrm{Na}\)), which, after emitting a beta particle, transforms into magnesium-24 (\({ }_{12}^{24} \mathrm{Mg}\)). The increase in the atomic number shows that a proton has been added!
Understanding beta minus decay is crucial, especially for those studying nuclear physics or chemistry. It demonstrates how elements can naturally transform, providing insight into the processes happening in stars and radioactive substances.

Beta plus decay (\(\beta^+\)) is when a proton in a nucleus turns into a neutron. During this process, a positron and a neutrino are emitted. You might be wondering, what is a positron? Simply put, it's the positively charged counterpart of an electron.
In beta plus decay,

• the mass number stays unchanged,
• while the atomic number decreases by 1.

This decay results in the original element turning into a different one. For instance, oxygen-15 (\({ }_{8}^{15} \mathrm{O}\)) becomes nitrogen-15 (\({ }_{7}^{15} \mathrm{N}\)) after a beta plus decay. Notice how the atomic number goes from 8 to 7? That's the proton turning into a neutron!
Beta plus decay is important in the study of particle physics and is used in medical applications like PET scans. It shows us the fascinating ways particles can transform, highlighting the dynamic nature of atomic structures.