24.2 The nucleus

• The nucleus of an atom contains positive protons and uncharged neutrons.
• The term nucleon is used to refer to the protons and neutrons in the nucleus of an atom.
• Isotopes are nuclei of the same element that have the same number of protons but different numbers of neutrons.
• One atomic mass unit is expressed as one twelfth the mass of a neutral carbon-12 atom.
• The radius of a nucleus is = R(0) x A^1/3, where R(0) is roughly the radius of a nucleus, and A is the nucleon number.
• The strong nuclear force acts between all nucleons, it is a very short range but effective force over just a few femtometers. The force is attractive to about 3fm and respulsive below 0.5 fm
• The radius of a nucleus is given by radius= 0.61 x h x c / E sin theta