From questions

• Fundamental particles are electrons, positrons, neutrino's and anti-neutrino's.
• When a nucleus decays, their is a decrease in mass, so energy is released given by Einstein's energy-mass equation. The binding energy increases; difference between the binding energies.
• Fusion of helium requires greater energy due to nucleus having a greater charge than hydrogen so more repulsive force, they need to get closer together, so more temperature and more EK to do so.
• For deuterium, the total mass of the individual nucleons is different from the mass of the deuterium nucleus because the mass of the nucleus is greater than the nucleon, energy must be supplied to the nucleus to free the nucleons.