1/5/09

Post date: Dec 10, 2008 12:2:26 AM

Bell Activity:

• • Just like elements, we give names to compounds to separate them from other compounds

  • Naming ionic compounds

    • Ionic compounds are formed because of attractions between positive and negative ions.

      • Positive ions

        • are positive because they gave up electrons (lost negative charges)

        • are called cations

        • Are usually formed by elements on the left side of the periodic table

      • Negative ions

        • are negative because the gained electrons (gained negative charges)

        • are called anions

        • Are usually formed by elements on the right side of the periodic table

    • Naming cations

      • use the name of the element, plus the word ion

      • ion charges are determined by number of valence electrons

      • cations will have + charge, with the charge number being the same as the number of valence electrons

        • Example: Sodium, Na

          • When sodium gives up electrons, it becomes an ion called sodium ion

          • Sodium is in the first column of the periodic table, so it has 1 valence electron

          • The charge of a Sodium Ion is 1+, so the symbol for this is Na 1+

        • Example: Barium, Ba

          • When barium gives up electrons, it becomes an ion called barium ion

          • Barium is in the second column of the periodic table, so it has 2 valence electrons

          • The charge of a Barium Ion is 2+, so the symbol for this is Ba 2+

    • Naming ions assignment

      • • Write the name and symbol of the ions formed by the following elements:

          • Lithium

          • Beryllium

          • Calcium

          • Cesium

          • Potassium

        • Example: For Sodium, the name of the ion is Sodium Ion and the symbol is Na 1+

        • We will add to this assignment, so don't turn it in yet

      • Some elements (transition metals) form more than one type of cation

        • With these elements, we must include some way to show which ion we're talking about

        • We do this with roman numerals to show the charge of the ion

          • Example: Iron, Fe

            • Iron can give up either 2 or 3 electrons, so it will have either a 2+ or 3+ charge

            • The Iron ion with a 2+ charge is written as Iron (II) ion

            • The Iron ion with a 3+ charge is written as Iron (III) ion

    • Naming Anions

      • use the name of the element, but change the ending to -ide, plus the word ion