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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 neutronsand 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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