Alpha decay is a type of radioactive decay in which an atomic nucleus loses two protons and two neutrons, resulting in the formation of a new element with an atomic number that is two less than the original element.

Beta decay is a type of radioactive decay in which an atomic nucleus emits an electron or a positron, resulting in the formation of a new element with an atomic number that is one more or one less than the original element.

Gamma decay is a type of radioactive decay in which an atomic nucleus emits a high-energy photon, resulting in the formation of a new element with the same atomic number as the original element.

Half-life is the term used to describe the amount of time it takes for half of the atoms in a radioactive sample to decay.

The half-life of a radioactive substance is equal to the reciprocal of the decay constant.

Activity is the term used to describe the number of disintegrations per second in a radioactive sample.

The SI unit of activity is the becquerel (Bq), which is defined as one disintegration per second.

Activity is inversely proportional to half-life.

Radioactive decay is the term used to describe the process by which a radioactive substance decays into a stable substance.

The three main types of radioactive decay are alpha decay, beta decay, and gamma decay.

Alpha decay is characterized by the emission of an alpha particle, which is a helium nucleus consisting of two protons and two neutrons.

Beta decay is characterized by the emission of a beta particle, which is an electron or a positron.

Gamma decay is characterized by the emission of a gamma ray, which is a high-energy photon.

Neutron decay is the process by which a neutron decays into a proton, an electron, and an antineutrino.

A radioactive decay chain is a series of successive decays in which a radioactive substance undergoes a series of decays until it reaches a stable state.