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What is simplified in this picture?

What is simplified in this picture?. The Thompson: Discovery of the Electron the Electron (Thomson). Cathode Ray Tube Charged particles produced (affected by magnetic field). Concluded that atom must have positive and negative parts Electron – negative part of the atom

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What is simplified in this picture?

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  1. What is simplified in this picture?

  2. TheThompson: Discovery of the Electronthe Electron (Thomson) • Cathode Ray Tube • Charged particles produced (affected by magnetic field)

  3. Concluded that atom must have positive and negative parts • Electron – negative part of the atom • Only knew the e/m ratio • Plum Pudding Model

  4. Charge and Mass of the Electron (Millikan) • Oil drop experiment • Determines charge on electron (uses electric field to counteract gravity) • Quantized • e = 1.602 X 10-19 C • m = 9.11 X 10-31 kg

  5. The Nucleus (Rutherford) • Gold Foil Experiment • Discovers nucleus (disproves Plum Pudding Model) • Planetary Model

  6. Atoms:Basic Facts Three particles

  7. Photo of a single Barium atom

  8. Atoms:Basic Facts • Size – Measured in Angstroms 1 A = 1 X 10-10 m 1 Cl atom = 2.0 A 5 million Cl atoms can be lined up in 1 mm.

  9. Atoms:Basic Facts • Mass – grams/mole H = 1.00794 grams/1 mole 1.00794 g/6.022 X 1023 atoms C = 12 g/mol

  10. Isotopes • Isotopes – Atoms with the same # of protons, but different # of neutrons Copper-63 29 p 34 n Copper-65 29 p 36 n 2. Atomic Mass –weighted average of all the isotopes

  11. Ions • Cation – Positive Ion • Anion – Negative Ion • Review Common Charges

  12. Stable vs. Unstable Nuclei Nuclear Changes • Most nuclei are stable – do not change • Some nuclei are unstable (radioactive) • Change into a different nucleus (decay) • Spontaneous process – happens naturally, by itself • Releases radiation Only nuclear reactions can change a nucleus. No chemical process can

  13. Radium  Radon + Radiation Decay -New element and alpha, beta, or gamma -lost mass becomes kinetic energy

  14. Types of Nuclear Radiation 2 p+ 2 n e-

  15. What Stops Radiation Al Foil Wood Lead. Iron, Concrete Paper Alpha () Beta () Gamma ()

  16. Decay Equations Alpha Decay 23892U 42He + 23490Th Beta Decay 23490Th0-1e + 23491Pa

  17. Decay Equations Gamma Decay Occurs with alpha and beta decay No change in atomic mass (gamma radiation has no mass 00)

  18. Decay: Ex 1 What product is formed when radium-226 undergoes alpha decay? 22688Ra 42He +

  19. Decay: Ex 2 What element undergoes alpha decay to form lead-208? 42He + 20882Pb

  20. Decay: Ex 3 What isotope is produced when thorium-231 beta decays? 23190Th 0-1e +

  21. Write the equation that describes oxygen-15 undergoing positron emission.

  22. Which nuclei are radioactive (unstable) • All elements have at least one radioactive isotope • All isotopes of elements heavier than Lead (82) 82 Pb 207.2 At least one radioactive isotope All isotopes are radioactive

  23. Transmutation • Rutherford(1919) – First successful alchemist 147N + 42He 178O + 11H • Modern methods • Particle Accelerators (Cyclotrons) • Use neutrons or other elements (creation of transuranium elements)

  24. Periodic Table • Dmitri Mendeleev – 1869 • Used atomic mass (modern is by atomic #) • Period – Across • Group – Down • Metals Non-Metals Metalloids - Semiconductors

  25. Periodic Table Group 1 Alkali metals Group 2 Alkaline earth metals Transition Metals Group 7 Halogens Group 8 Noble Gases Lanthanides Actinides Discuss placement of Lanth/Act

  26. Average Atomic Mass Atomic Mass – Weighted Average of all the isotopes

  27. Average Atomic Mass Calculate the ave atomic mass of Boron if it exists as 19.90% Boron-10 (10.013 g/mol) and 80.10% B-11 (11.009 g/mol)? (Ans: 10.811 g/mol)

  28. Mixing Elements Ionic = Metal + Non-metal (NaCl) Molecular = Non + Non (CH4) Alloy = Metal + Metal • Stainless steel (Fe/Cr) • Brass (Cu/Zn) • Bronze (Cu/Sn)

  29. Ionic vs. Molecular

  30. Ionic Solids

  31. Ionic vs. Molecular Ionic or molecular? HCl CO2 VO3 H2O BaF2

  32. What ionic compound would form between: Ba and Cl Ba and Te Al and S Fe3+ and O Fe2+ and O

  33. Naming Ionics • Binary Compounds Gr I and Gr II metals (and Aluminum) NaCl BaO Al2O3 magnesium bromide aluminum sulfide potassium oxide

  34. Naming Ionics • Compounds with Polyatomics Sodium hydroxide Sodium carbonate Aluminum Sulfate NaNO3 Ca(OH)2 (NH4)3PO4

  35. Mixed Examples Magnesium Sulfide Magnesium Sulfite Magnesium Sulfate Lithium Phosphide Lithium Phosphate Ba(ClO3)2 BaCl2

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