Where do atoms come from? Are new atoms being made right now on the earth? If so, how? Where?

2. Where do atoms come from? • Are new atoms being made right now on the earth? • If so, how? Where? • Are new atoms being made anywhere right now? • If so, how? Where?

3. Elements • Elements - contain only one type of atom • 90 naturally occuring elements (Uranium, 92 heaviest naturally occuring) • Transuranium (synthetic) elements • Types of elements a) Monoatomic – Fe, Au b) Molecular – H2, N2, O2, P4, C60

5. Origin of the Elements

6. Origin of the Elements

7. Supernova Remnant

8. Origin of the Elements Abundance (by mass) Earth’s Crust: 46% O Body: 65 % O Universe: 90% H and 10% He

9. History: The Atom Democritus 1. Atomos – Indivisible (~400 B.C.) 2. Smallest particle of a substance that retains the properties of that substance 3. Only “Atoms and the Void”

11. History: The Atom John Dalton’s Atomic Theory (1803) • All matter is made of indivisible particles called atoms • Atoms of same element have same properties • Atoms combine in small, whole # ratios • Chemical reactions are merely the rearrangement of atoms

12. Symbols for Elements Jons Berzelius – standardized names and symbols of the elements Strontium = Sr

14. Names for Elements a. Greek & Latin Na = Natrium K = Kalium Li = Lithos b. Places (Ge, Fr, Cf) Y, Yb, Er, Tb = Ytterby c. Scientists (Es, Fm, Cm)

15. History: The Electron J.J. Thomson (1897) – discovered the electron with a Cathode Ray Tube

16. History: The Electron

17. History: The Electron

18. History: The Electron

19. History: The Electron

22. History: The Electron Thomson Plum Pudding Model

23. History: The Nucleus Rutherford (1911) • Discovered Nucleus • Gold Foil Experiment

24. History: The Nucleus 1:8000 bounced back (10,000 miles/s)

26. History: The Nucleus

27. History: The Nucleus 3. Results a. Nucleus is heavy and dense b. 99.9% of atom’s mass is in the nucleus c. Electrons “orbit” the nucleus d. Most of the atom is empty space

29. History: The Proton Rutherford (1914) • Had been suspected to exist since 1886 (Goldstein’s canal rays) • 1836 times heavier than the electron

30. History: The Neutron • Discovered last (1932) by Chadwick • Roughly same mass as proton

31. The World’s Most Famous Neutron

32. Particle Charge Mass Proton +1 ~1 g/mol Electron -1 0.00055 g/mol (1/1836) Neutron 0 ~1 g/mol

34. Scanning Tunneling Microscope History: The Atom

35. History: The Atom

37. Protons, Neutrons and Electrons Reading the boxes 3 9 Li F 6.941 18.994

38. Isotopes 1. Isotopes – Atoms with the same # of protons, but different # of neutrons • Elements often exist as a mixture of isotopes Protons Neutrons Electrons Copper-63 Copper-65

39. p n E 92Zr 38 50 38 233Th 11 13 11 55 79 55 Isotopes

40. Isotopes • Cancer treatment (60Co gives off gamma rays) • Medical Tracers (24Na for circulatory system) • 14C dating a. Mummies b. Shroud of Turin 4. Nuclear fuel (235U and 239Pu)

44. Isotopes • Some isotopes are more common • Hydrogen example 1H 2H (deuterium) 3H (tritium) 3. Atomic Mass – Weighted Average of the isotopes

46. Average Atomic Mass 4. What is the ave atomic mass of Gallium if it exists as 60.30% 69Ga (68.926 g/mol) and 39.70% 71Ga (70.926 g/mol)? (Ans: 69.72 g/mol)

47. Average Atomic Mass 5. Out of 400 chlorine atoms, 302 are 35Cl (34.969 g/mol), and 98 are 37Cl (36.966 g/mol). Average atomic mass?

48. What is average atomic mass of Copper if 69.09% exists as 63Cu (62.9298 g/mol) and the rest exists as 65Cu (64.9278 g/mol)? (0.6909)(62.9298) = 43.48 ( )(64.9278) = 20.07 63.55 g/mol

49. p n e 16O2- 23Na+ 9 10 10 26 30 23 17 18 18 Ions • Cation – positive ion (more p than e) • Anion – Negative ion (more e than p)

50. p n e 13C 90Sr 16 16 14 16 18 18 24Mg2+ 35 44 36 19 21 18 15N3- Ions