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

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?. Elements. Elements - contain only one type of atom 90 naturally occuring elements (Uranium, 92 heaviest naturally occuring)

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

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  1. 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?

  2. 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

  3. Origin of the Elements

  4. Origin of the Elements

  5. Supernova Remnant

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

  7. 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”

  8. 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

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

  10. 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)

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

  12. History: The Electron

  13. History: The Electron

  14. History: The Electron

  15. History: The Electron

  16. History: The Electron Thomson Plum Pudding Model

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

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

  19. History: The Nucleus

  20. 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

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

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

  23. The World’s Most Famous Neutron

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

  25. Scanning Tunneling Microscope History: The Atom

  26. History: The Atom

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

  28. 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

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

  30. 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)

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

  32. 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)

  33. 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?

  34. 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

  35. 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)

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

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