The Atom
- All matter is composed of elements
- All elements are composed of atoms
- The atom is composed of:
–Nucleus: - neutrons - protons
–Orbital
Shell: - electrons
- Stable
atoms have a balance of protons and neutrons.
- Radioactive atoms contain excess
energy, and the ratio of protons to neutrons is too low or too high
![](https://afcf.umaryland.edu/ehs/public/uploads/UMB RadiationSafety/slide6.jpg)
![](https://afcf.umaryland.edu/ehs/public/uploads/UMB RadiationSafety/slide6.jpg)