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Chemistry SM-1131 Week 5 Lesson 1

Chemistry SM-1131 Week 5 Lesson 1. Dr. Jesse Reich Assistant Professor of Chemistry Massachusetts Maritime Academy Fall 2008. Class Today. Test Wednesday Poem Movie Review: Periodic Table, Isotopes and Atomic Mass Atomic Mass Review for the test. Quote.

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Chemistry SM-1131 Week 5 Lesson 1

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  1. Chemistry SM-1131Week 5 Lesson 1 Dr. Jesse Reich Assistant Professor of Chemistry Massachusetts Maritime Academy Fall 2008

  2. Class Today • Test Wednesday • Poem • Movie • Review: Periodic Table, Isotopes and Atomic Mass • Atomic Mass • Review for the test

  3. Quote • Everything has to change, and that change has to start with me. -Utah Phillips Just be careful because change will hurt. -D. Reich

  4. Oil drop Movie • http://chemistry.umeche.maine.edu/~amar/fall2004/Millikan.html

  5. Skipping Ahead • I’m skipping a lot of scientists and a lot of story • We have a nucleus and it contains Protons and Neutrons • Electrons are on the outside in set patterns

  6. Nucleus Masses • Protons have masses of 1.67262e-27kg • Neutrons have masses of 1.67493e-27kg • OK, talking about that mass is obnoxious. So chemists came up with another scheme. They took an atom of Carbon, which has 6 neutrons and 6 protons, and they said 1/12 of that mass is now 1 amu. • Protons by themselves have a mass of 1.0073 amu. Neutrons have a mass of 1.0087 amu.

  7. Electrons • Protons are over 1800 times larger than electrons. So, chemists say electrons have no mass. • This is not exactly true, it’s more like they have negligible mass.

  8. Charge • Protons have a charge of +1 • Electrons have a charge of -1 • Neutrons have no charge at all. • Oppositely charged particles attract. • Similarly charged particles repel. • If an atom has an equal number of protons and electrons the atom has no charge. For every extra proton it has +1 charge. For every extra electron it has -1 charge.

  9. Periodic Table Hydrogen is the element 1 is the atomic number 1.0079 is the atomic mass

  10. Elements • The number of protons is called the atomic number. • If two elements have the same atomic number they are the same element. If two elements have different atomic numbers they are different.

  11. The Table Groups/families are up and down Rows/periods are left to right

  12. The Table Group 1. Alkali Metals Group 2. Alkaline Earth Metals Group 3-12 Transition Metals Group 17. Halogens Group 18. Noble Gases Main group 1,2 13-18 H, C, N, O, P, S, Se are organic elements 57-71 lanthanides 89-103 actinides B, Si, Ge, As, Sb, Te, Po are metaloids

  13. Metals • Shiny • Reflect • Malleable (bendable) • Ductile (can be drawn into strips) • Conduct electricity • LOSE ELECTRONS

  14. Non-Metals • Dull • Brittle • Don’t conduct • GAIN ELECTRONS (think graphite)

  15. Metalloids • Mixed Properties • Semiconductors • Some dull, some shiny • Etc.

  16. Ions • Any charged particle is called an ion. • # of Protons - # of Electrons = charge • If # of protons = # of electrons the charge is 0 and we call it neutral (not an ion) • If # of protons > # of electrons it has a positive charge and we call it a cation. • If # of protons < # of electrons it has a positive charge and we call it an anion.

  17. Isotopes • If two elements are the same they will have the same # of protons. • If two atoms of the same element have different numbers of neutrons they are called Isotopes.

  18. Ways to write Isotopes • Two systems exist to write Isotopes. • Let’s take Chlorine for Example. There are two major isotopes of chlorine. One where the atom has 17 protons and 18 neutrons and one where it has 17 protons and 20 neutrons. • The easy way to write it is Cl-35 or Cl-37. • Or 3517Cl, and 3717Cl. • Top number = Mass # • Bottom = Atomic Number (# of protons)

  19. Mass Number • Simply put the mass is: • # of protons + # of neutrons = atomic number

  20. Atomic Mass • Atomic Mass is actually pretty complex. It’s an average mass of all the different isotopes. (%abundance * mass) + (%abundance*mass) etc… = atomic mass

  21. Neon • Neon is made up to 3 isotopes • Ne-20 = 90.38% • Ne-21 =0.27% • Ne-22 = 9.25% • Atomic mass = 20.00*.9038 + 21.00*.0027 + 22.00*.0925 = 20.1677 = 20.17 amu = atomic mass So the masses on the periodic tables are average masses of all the isotopes

  22. Get Ready • TEST WEDNESDAY!!! • 1: scientific method, vocab words • 2: sig fig, rounding, density • 3: Matter and Energy, chemical vs. physical, temperature, heat capacity • 4: Atomic Theory, scientists, protons, neutrons, electrons, periodic table, Ions, Isotopes, Atomic Mass, Atomic Number

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