Mini-summary moment:

• Types of decay are alpha, beta and gamma
• Alpha involves ejecting an alpha particle (two neutrons and two protons, or helium nucleus, and somehow picking up two electrons on the way to become a full helium atom), for example:

$$ {_{92}^{238}}U \rarr {2^4}He + {{90}^{234}}Th $$

• Beta involves ejecting a beta particle, where there are two cases:

  • A neutron decays into a proton by releasing an electron, the beta particle (and also a down quark decaying into an up quark, but that’s too advanced for now), for example:

  $$ {{90}^{234}}Th \rarr {{ -1}^{0}}e + {_{91}^{234}}Pa $$

  • A proton decays into a neutron by releasing a positron (this may make no sense either but if I can make a lesson on subatomic particle constituents I promise this will be explained there), for example:

  $$ {_4^7}Be \rarr {_3^7}Li + {_1^0}e $$

• Gamma involves a ejection of a gamma ray, hence it is also called gamma emission, where a nucleus in an excited state releases a huge amount of energy in the form of a high frequency electromagnetic wavelength

$$ {_{92}^{238}}U^* \rarr {2^4}He + {{90}^{234}}Th + 2{_0^0}\gamma $$