1. James Chadwick By: Alyssa Cerino, Steven Venit, and Eric Stewart

2. Previous Atom Model ●Developed theory on the atom's nucleus ●The existence of a neutron or a non charged particle inside the atom's nucleus ●Atomic number less than atomic mass ●Researchers discovered neutrons weren't the only particle in the nucleus

3. Experimental Design ●Alpha particles are launched at Beryllium. ●Beryllium emits a “mystery radiation”. ●The particles emitted by this radiation are deemed uncharged, because they could not be affected by a magnetic field. ●When these particles collide with certain surfaces, they discharge protons.

4. Reasoning for the Development of a New Model ●A scientist named Ernest B. Rutherford proposed the idea that there could be a particle with mass but no charge ●He called this particle the neutron ●He imagined the particle was an electron and a proton paired together ●Rutherford provided no evidence of this idea ●This inspired Chadwick to prove him wrong

5. The New Atomic Model ●Added the Neutron ●The overall charges remained the same ●There no longer seemed to be a discrepancy between atomic mass and number

6. Interesting Facts 1.The main character of a TV show, Jimmy Neutron, was named after James Chadwick because of his discovery of the neutron. 2.Chadwick received a Nobel Prize for his discovery of the neutron in 1932

7. Works Cited Slide 2: http://atomic-molecular-optical- physics.suite101.com/article.cfm/the_discovery_of_the_neutron Slide 5: http://www.nobelprize.org/nobel_prizes/physics/laureates/1935/chadwick- facts.html Slide 1: http://www.thocp.net/biographies/chadwick_james.htmhttp://www.thocp.net/biographies/chadwick_james.htm