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NOTES: A.7 – What Determines Properties? PowerPoint Presentation
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NOTES: A.7 – What Determines Properties?

NOTES: A.7 – What Determines Properties?

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NOTES: A.7 – What Determines Properties?

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  1. NOTES: A.7 – What Determines Properties?

  2. • We have seen that atoms of different elements will react with different numbers of chlorine atoms or oxygen atoms. EXAMPLE: Li LiCl Mg MgCl2 Al AlCl3 C CCl4

  3. EXAMPLE: Li Li2O Mg MgO Al Al2O3 C CO or CO2

  4. WHY IS THIS? **Recall: atoms of different elements have different numbers of PROTONS (ATOMIC NUMBERS)…this means that they also have different numbers of ELECTRONS. **Many properties of elements are determined by the number of electrons in their atoms and how these electrons are arranged.

  5. • A major difference between atoms of METALS and NONMETALS is: metal atoms lose some of their electrons much more easily than nonmetal atoms do

  6. As a result, metals exhibit certain properties:  metal atoms tend to lose 1 or more outer electrons to other atoms or ions…so metallic elements tend to form POSITIVE IONS (CATIONS).

  7. Metallic Properties:  metal atoms are strongly attracted to one another…this leads to: - higher melting points - solid at room temperature - higher densities than the nonmetals

  8. EXAMPLE: Magnesium has a melting point of 651°C and sodium has a melting point of 98°C. What does this mean? • the attractions among the atoms of magnesium metal must be stronger than those in sodium metal

  9. PRACTICE: Use your periodic table and the examples provided to PREDICT the chemical formulas for the compounds that would form between the following elements:

  10. KNOWN COMPOUNDS: NaI MgCl2 CaO Al2O3 CCl4 PREDICT the formula for a compound formed from: a) C and F: b) Al and S: c) K and Cl: d) Ca and Br: e) Sr and O:

  11. KNOWN COMPOUNDS: NaI MgCl2 CaO Al2O3 CCl4 PREDICT the formula for a compound formed from: a) C and F: CF4 b) Al and S: Al2S3 c) K and Cl: KCl d) Ca and Br: CaBr2 e) Sr and O: SrO