The Composition of the Nucleus
1. Matter is made up of very small particles called atoms.
2. Each atom has a very small and very dense core known as the
3. Most of the mass of the atom is contained in the nucleus.
1. Radioactivity is the spontaneous and random emission of radioactive rays from unstable radioactive
materials after which they become more stable.
2. The process is said to be spontaneous because it is not influenced by any p