Binding energy is the amount of energy required to separate the individual particles in an atom's nucleus. Helium-4 has a high binding energy, meaning that it takes a significant amount of energy to break apart the nucleus of this atom.
The high binding energy of helium-4 is significant because it makes this isotope very stable. This stability allows helium-4 to serve as a building block for larger atoms, as well as playing a crucial role in the nuclear fusion reactions that power stars.
Binding energy is typically measured in units of electron volts (eV) or in joules (J). For helium-4, the binding energy is often expressed as either the total binding energy (the energy required to completely separate the nucleus into its constituent particles) or the binding energy per nucleon (the average amount of energy required to remove a single nucleon from the nucleus).
Helium-4 has the highest binding energy per nucleon of any element. This means that, pound for pound, helium-4 contains the most energy of any atom. This high binding energy is a result of the strong nuclear force that holds the two protons and two neutrons together in the nucleus.
While the binding energy of helium-4 is incredibly high, it is difficult to harness for practical applications. The process of nuclear fusion, which releases the binding energy of helium-4, requires extremely high temperatures and pressures. Researchers are actively studying ways to harness this energy for use in fusion reactors, but it is not yet a viable source of energy production.