1. Law of Physics chapter 18 A moving charge looses energy = electron would eventually be pulled into the nucleus = Rutherford atom would be unstable

2. New ideas as to the parts of and arrangement of an atom Proton + Rutherford 1917 Neutron neutral Chadwick 1932 Electron – Thomson 1897

3. Carbon 12 Nuclear symbolism mass number protons + neutrons 12 C atomic number = # of protons 6 6 electrons - 6 protons + 6 neutrons

4. Carbon 14 Isotope = same element with different mass (more neutrons) mass number protons + neutrons 14 C atomic number = # of protons 6 6 electrons – 6 protons + 8 neutrons

5. Atomic number determines which element Mass number determines the isotope-same atomic number, different mass because of amount of neutrons. There is usually more than one type of isotope for all atoms

6. Atomic mass unit Chadwick -1932 neutron amu = 1.008666 = 1 Rutherford -1919 proton amu = 1.007276 = 1 Thomson -1897 electron amu =.0005486 = 0

7. Carbon 12 1 atomic mass unit = 1/12 the mass of a carbon atom Mass of Carbon = 12.00000amu 6 protons = 6 x 1.007 = 6.042 6 neutrons = 6 x 1.009 = 6.054 6 electrons = 6 x.0005 =.003 6.042 + 6.054 +.003 = 12.099

8. .009 is the mass that is lost. It goes to energy and is called the nuclear binding energy. With this absence, the nucleolus will not fly apart. E = MC 2 The natural tendency of the nucleolus is to repel the + charges and fly apart. The deficient of the amu.009 holds it together. Overcomes repulsion from neutrons and protons P-P, P-N, N-N Strong nuclear force

9. Atomic mass/weight Atomic mass = mass of a given isotope of an element Carbon 12 or Carbon 14 Atomic weight = weighted average of the atomic masses of all the naturally occurring isotopes of an element

10. Atomic weight % abundance of naturally occurring isotopes by Atomic mass 12.00 = 99.0% 13.02 = 0.10% 14.04 = 0.90% 12.00 x.9900 = 11.88amu 13.02 x.0010 =.0130amu 14.04 x.0090 =.13amu 11.88 +.0130 +.13 = 12.023amu = 12.02amu = atomic weight of Carbon. The others are isotopes (Carbon 14)