12/12/08

Post date: Dec 11, 2008 9:13:57 PM

Bell activity: Why do we have 3 different ways to model a compound?

• • Bonds can bend, stretch, and rotate without breaking.

    • Atoms are constantly in motion, vibrating and spinning around, but this does not break the bond

    • We usually show a bond with a solid line, but it really behaves more like a flexible spring

  • The chemical structure of a compound determines its properties

    • Network structures

      • Repeating patterns of atoms - demo with students as atoms

      • Some networks are made of ions

        • Each atom is attracted to all the atoms around it

      • Very strong structures with high boiling and melting points

    • Molecules

      • Molecules are strongly bonded atoms

      • Each molecule is attracted to others around it, but not nearly as strong of an attraction.

      • Strength of attractions between molecules varies

    • Properties determined by chemical structure

      • Melting point and boiling point

      • Hardness

• Section 1 Review due Monday

  • • Page 182: 1-6

• • Missing and make-up work must be turned in before Winter Break (next Friday)

    • States of matter quiz can be corrected for up to half the points lost

      • On a separate sheet, write a complete sentence answering the questions in your own words

    • Oobleck projects may be corrected for up to full credit

      • To be considered, Oobleck project must be typed and include ALL required elements (see Oobleck assignment sheet or Oobleck rubric in the "handouts" section for details.

    • Late assignments may be turned in for partial credit