Answer
Alpha particles are helium nuclei, consisting of 2 protons and 2 neutrons. They have a charge of +2e and an atomic mass value of 4 u.
Beta particles are either electrons or positrons. They have a charge of –e or +e, respectively. They are about 8000 times less massive than alpha particles.
Gamma rays are photons, high-energy quanta of electromagnetic radiation. They have no charge and no mass.
Work Step by Step
Gamma radiation is an EM wave of photons and as such it is extremely difficult to block. Alpha particles are helium nuclei with a greater mass and stronger charge, making them easy to deflect; They do not even penetrate human skin. Beta particles fall in between.