5/13/09

Post date: May 13, 2009 12:3:6 PM

Bell Ringer: Write the formulas for Hydrogen sulfide, Calcium oxide, and Magnesium fluoride.

    • Naming ionic compounds

      • compounds consist of an anion and a cation

      • Write the name of the anion and the cation

      • Put the two together, with the cation's name first

      • If the cation is a transition metal

        • Find the charge on that transition metal by reversing the cross you did in the last step. If there is one of each type of ion in the compound, the transition metal has the same number (but opposite sign) as the anion.

        • Use roman numerals to indicate which charge that cation has

  • Naming assignment

      • Given the following formulas, write the name of each ionic compound

        1. LiCl

        2. BeF2

        3. Ca2C

        4. HBr

        5. Fe2O3

    • Naming Covalent Compounds

      • Slightly different from ionic compounds

    • Made from two elements on the right side of the table

      • Element farther to the left on the periodic table is named first

      • Element on right on periodic table is named second, and the ending is changed to -ide.

    • Use prefixes to tell how many of each atom is in a molecule. If there is only one of the first atom, no prefix is needed

      • Example: One atom of Boron bonds with three atoms of fluorine, BF3

        • Boron is farther to the left, so it is named first

        • Fluorine is farther to the right, so it comes second and changes to fluoride

        • There are 3 fluorine atoms, so we put the prefix "tri" in front of fluoride

        • Name: Boron trifluoride

      • Example: Two atoms of Nitrogen bond with 4 atoms of Oxygen, N2O4

        • Nitrogen is on the left, named first

        • Oxygen is on the right, named second and changed to oxide

        • 2 Nitrogens, so use the prefix "di"

        • 4 oxygens, so use the prefix "tetra"

        • Name: Dinitrogen tetroxide

    • Naming assignment

        • Given below are either the name or the formula for covalent compounds. Complete the table with the missing names or formulas.

    • Empirical Formulas

      • Smallest ratio of atoms in a compound

      • For ionic compounds, the chemical formula is the same as the empirical formula

      • For covalent compounds, the two may or may not be the same

        • Example: H2O is the molecular formula for water. It is also the smallest ratio, so it is the empirical formula as well.

        • Example: C6H12O6 is the molecular formula for glucose. They all have a common factor of six, so if we divide the numbers by 6, we get CH2O, which is the empirical formula.

      • Using masses to find the empirical formula

        • Given the mass of a certain element in a compound for each element

        • Divide each mass by the element's atomic mass

        • smallest whole number ratio of these numbers tells number of each atom for empirical formula

        • Example: Page 196

  • Naming assignment

      • Add on page 196: 1-7