What happens to an atom when it emits a beta particle?

Radioactive decay is a spontaneous process by which an unstable atomic nucleus loses energy by emitting radiation. This can occur in several ways, including alpha decay, beta decay, and gamma decay.

In this natural phenomenon, an element transforms into another at a fixed rate known as the half-life, which is unique for each radioactive isotope. Because of this rate, radioactive decay is widely used in dating techniques for geological and archaeological artifacts. Each decay process follows particular rules and results in different changes to the nucleus, leading to the emission of various particles or electromagnetic waves.

Beta particle emission is one of the types of radioactive decay. In this process, beta particles, which are high-energy, high-speed electrons (beta-minus) or positrons (beta-plus), are ejected from the atomic nucleus. Electrons are negatively charged, whereas positrons are their positively charged counterparts.

Beta-Minus Decay

During beta-minus decay, a neutron in the atom's nucleus converts into a proton, releasing an electron and an antineutrino. This electron is what we know as a beta-minus particle. It carries away a negative charge and a significant amount of energy.

Beta-Plus Decay

Conversely, in beta-plus decay, a proton is transformed into a neutron, emitting a positron and a neutrino. The positron, or beta-plus particle, is detected when it annihilates with an electron, producing a pair of gamma-ray photons.

The emission of beta particles can alter the chemical and physical properties of the original element, often leading it to become more stable.

One significant result of beta decay is the transformation of the atomic number, which defines the identity of an element. When a neutron turns into a proton during beta-minus decay, the atomic number of the atom increases by 1, thus changing the element. This is because the atomic number corresponds to the number of protons in the nucleus, and the element's position in the periodic table is based upon this number.

For instance, if carbon with an atomic number of 6 undergoes beta-minus decay, it will transform into nitrogen, with an atomic number of 7. Conversely, during beta-plus decay, the atomic number decreases by 1 as a proton is converted into a neutron. A nitrogen atom (atomic number 7) undergoing beta-plus decay would transform into carbon (atomic number 6).

The mass number, however, remains unchanged in both scenarios, as it represents the total count of protons and neutrons in the nucleus. These transformations have profound implications in fields such as nuclear medicine, where certain isotopes are used for diagnosis and treatment.