Key concept 1: Nuclear decay reactions must obey the Law of Conservation of Mass.
Key concept 2: Nuclear decay reactions obey the Law of Conservation of Charge.
Put simply, this means the products have to add up to equal the decaying reactant (parent nuclide or isotope.) We need to pay attention to charges and to total mass.
It begins with the Nuclear Symbol
Atomic mass (protons + neutrons)
23592U
Atomic number (number of protons)
Radioactivity is the particles and energy emitted from an unstable nucleus to become stable. Sometimes it takes several steps.
Common radiation includes
| alpha | 42 He | Helium nucleus |
| beta | 0-1e | electron from nucleus |
| gamma | ultra high energy photons | |
| positron | 0+1e | positively charged electron |
| neutron | 10n | neutron ejected from nucleus |
Examples of nuclear decay reactions
alpha decay
23592U ==> 42 He + 23190Th
beta decay
146C ==> 0-1e + 147N
positron decay
2211Na ==> 0+1e + 2210Ne
fusion reaction with neutron emission
21H + 31H ==> 42He + 10
Each of these reactions are also accompanied by the release of energy as gamma rays (high energy photons).