1. Nucleus

2. Nuclear Notation  The nucleus consists of protons and neutrons. Protons: Z (atomic number) Neutrons: N Nucleons: A = Z + N (atomic mass) Full notation shows A, Z  Chemical symbol duplicates atomic number. Short notation – A only

3. Nuclear Size  All nuclei have about the same density . Independent of AIndependent of A  The nucleus is roughly a sphere. Radius r, r 0 = 1.2 fmRadius r, r 0 = 1.2 fm Volume VVolume V

4. Isotopes  Nuclei that have the same proton count are isotopes. Isotones for identical neutron countIsotones for identical neutron count

5. Nuclear States

6. Atomic Mass  Energy measurements for nuclear physics are built on the electron volt (eV). 1 eV = 1.6  10 -19 J1 eV = 1.6  10 -19 J  Mass is expressed in terms of the rest energy.  Mass is also expressed in terms of nucleons. Atomic mass unit (u)Atomic mass unit (u) Based on 12 CBased on 12 C 1 u = 931.5 MeV/c 21 u = 931.5 MeV/c 2  Proton, p 938.3 MeV/c 2 1.007 u  Neutron, n 939.6 MeV/c 2 1.009 u  Electron, e 0.511 MeV/c 2 5.546  10 -4 u

7. Mass Difference  The mass (M) in u is nearly equal to the atomic number (A).  Tables of isotope data frequently list  = M – A. Binding energyBinding energy  1 H;  = 7.29 MeV  4 He;  = 2.42 MeV  56 Fe;  = – 60.60 MeV  214 Pb;  = – 0.15 MeV  218 Po;  = 8.38 MeV  222 Rn;  = 16.39 MeV  226 Ra;  = 23.69 MeV

8. Binding Energy next