Radioactive Decay

What is Radioactive Decay? A change in an atom’s nucleus due to the emission of an alpha, beta or gamma radiation.

Alpha Particle Two Protons Two Neutrons 42He+2 Easily stopped by a piece of paper

Alpha Decay Radioactive decay where an alpha particle is released The radioactive element loses two protons and two neutrons Atomic number drops by two Atomic mass drops by four

Example of alpha decay Show how 22688Ra undergoes alpha decay Atomic mass = 226-4 = 222 Atomic number = 88-2 = 86 Element with atomic number of 86 = Rn 22688Ra = 42He + 22286Rn

Beta Particle A fast-moving electron ejected from a nucleus. Created when a proton splits into a neutron and an electron. Can be stopped by aluminum foil. 0-1e

Beta Decay Radioactive decay where the nucleus releases a beta particle The radioactive element converts one neutron into a proton and an electron. Atomic mass remains the same Atomic number increases by one

Example of Beta Decay Show how 21088Rn undergoes beta decay Emits a beta particle =0-1e Atomic mass = stays the same = 210 Atomic number = 88+1 = 89 21088Rn = 21089Ac + 0-1e