A nucleus emits an alpha particle ($\alpha$ or $\mathrm{He}^{2+}$), decreasing the atomic number by 2 and the mass number by 4.

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

A proton transforms into a neutron, emitting a positron ($e^+$ or $\beta^+$) 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.

An unstable nucleus spontaneously transforms to achieve stability by emitting particles and energy.

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.