Nuclear Reactions


Property Alpha Radiation Beta Radiation Gamma Radiation
Definition Helium nucleus High-speed electron High-energy EM wave
Charge +2 1 0
Mass 4 AMU 11800 AMU 0
Stopped by Sheet of paper Millimetres of aluminium Centimetres of lead
Ionising ability Strong Medium Weak
Distance through air A few centimetres A few metres A few kilometres

Nuclear Binding Energy

Different atoms have different binding energies per nucleon. If the product of a nuclear reaction has a higher nuclear binding energy than the reactants, energy is released.

Elements with a mass number less than iron can only release energy by fusion, and elements with a mass number greater than iron can only release energy by fission. This is why iron is the heaviest element producible in a star - with heavier elements only achievable during a supernova due to the immense amounts of energy available.