Radiometric Dating and Radioactive Decay

Study Notes

Radiometric dating determines a rock's age using the decay rate of radioactive isotopes.
Rocks contain naturally radioactive elements, such as uranium.
These radioactive elements decay into other elements at fixed rates.
Radiation emitted from rocks can be measured to calculate when the rock was formed.
Radiometric dating helps to predict the geological history of the Earth and its age.

Radioactive decay is when an unstable atomic nucleus loses energy by emitting radiation.
Elements exist as isotopes, wherein atomic nuclei contain the same number of protons but different numbers of neutrons.
Nuclides are isotopes that are unstable and undergo radioactive decay.
Unstable nuclides release energy and transform into different nuclides.
The unstable nuclide that undergoes radioactive decay is the parent nuclide.
The nuclide that results from radioactive decay is the daughter nuclide.

Alpha decay is a type of radioactive decay where an alpha particle is emitted.
An alpha particle consists of two protons and two neutrons bound together.
An alpha particle is the same as a helium nucleus.
A parent nucleus that is too big or has too many protons may undergo alpha decay to achieve a more stable state.
During alpha decay, the parent nucleus emits two protons and two neutrons.

Beta decay happens when a parent nucleus has a neutron-to-proton ratio that is too great.
Beta decay is a type of radioactive decay where a beta particle is emitted.
A beta particle is an electron emitted from the nucleus.
During beta decay, a neutron emits an electron (beta particle) and turns into a proton.

Gamma decay does not release a particle, unlike alpha and beta decay.
Gamma decay emits energy.
Gamma decay is a type of radioactive decay where a gamma ray is emitted.
A gamma ray is a high-energy photon.
During gamma decay, an atomic nucleus releases energy, moving to a lower energy state to become more stable.