1. DISCOVERY OF THE NUCLEUS: PROTONS AND NEUTRONS

2. ERNEST RUTHERFORD Determined the structure of the atom First to split the atom

3. HANS GEIGER Inventor of the Geiger counter to measure radiation

4. ERNEST MARSDEN Found that a few scattered alphas at angle over 140 degrees from the beam Alpha particles-helium without electrons (positive)

5. JAMES CHADWICK In 1932, Chadwick made a fundamental discovery in the domain of science; he proved the existence of nuetrons He prepared the way towards the fission of uranium 235 and towards the creation of the atomic bomb He was awarded the Hughes Medal of Royalty Society (1932) and Nobel Prize for Physics (1935)

6. EXPERIMENTS Ernest Rutherford  Worked with Geiger and Marsden to prove that the nucleus is positive Hans Geiger  Involved in a number of experiments that lead to Rutherford’s breakthrough theory of the atom Ernest Marsden  Experiments to study the scattering of alpha particles by thin metal foils James Chadwick  Worked with Rutherford, thought there had to be more to an atom because the atomic mass was too large.