An unstable nucleus emits an alpha particle ($^4_2He$). The atomic number decreases by 2, and the mass number decreases by 4.

A neutron in the nucleus transforms into a proton, emitting an electron ($e^-$) and an antineutrino ($\bar{v}$). The atomic number increases by 1, while the mass number remains the same.

A proton in the nucleus transforms into a neutron, emitting a positron ($e^+$) and a neutrino ($v$). The atomic number decreases by 1, while the mass number remains the same.

An excited nucleus releases energy by emitting a gamma ray photon ($\gamma$). The atomic number and mass number remain unchanged.

The neutron transforms into a proton, emitting an electron and an antineutrino.

The proton transforms into a neutron, emitting a positron and a neutrino.

The process where unstable atomic nuclei release energy and particles to become more stable.

A particle consisting of two protons and two neutrons, equivalent to a helium nucleus ($mathrm{He}^{2+}$).

An electrically neutral particle with nearly zero mass, emitted in beta-plus decay.

A particle with the same mass as an electron but with a positive charge, also known as an antielectron ($e^{+}$ or $\beta^{+}$).

An electrically neutral particle with nearly zero mass, emitted in beta-minus decay.

A high-energy photon emitted by an excited nucleus during gamma decay ($gamma$).

The atomic number decreases by 2.

The atomic number increases by 1.

The atomic number decreases by 1.

Both the atomic number and mass number remain unchanged.

An unstable neutron-to-proton ratio within the nucleus.

The mass number of the atom decreases by 4.