1. Chapter 3 Molecules, Compounds, & Chemical Equations CHE 123: General Chemistry I Dr. Jerome Williams, Ph.D. Saint Leo University

2. Overview Chemical Bonding Chemical Formulas Chemical Nomenclature –Ionic Bonding

3. Chemical Bonding Compounds are composed of atoms held together by chemical bonds. Interaction of electrons between elements is what results in chemical bonding.

4. Chemical Bonding Two broad types of chemical bonds. –Ionic Bonding involves the transfer of electrons from a metal to a nonmetal. –Covalent Bonding involves the sharing of electrons between nonmetal atoms.

8. Chemical Formulas Compounds are most easily represented using chemical formulas for the individual constituent elements and whole number subscripts to denote how many atoms of that element are present.

9. Chemical Formulas Review Ways to Write Chemical Formulas –Empirical Formula –Molecular Formula –Structural Formula –Ball-and-Stick Model –Space-Filling Model

17. Chemical Nomenclature Review the following concepts –Elements (Atomic & Molecular) –Molecules –Diatomic Molecules (know the magic seven) –Ion (know how cations & anions form) –Polyatomic Ion –Ionic Bonding –Covalent Bonding

20. Chemical Nomenclature What type of Bonding is Present? –Determines the system (rules) one uses to name things. –Works about 95 – 97% of time. The remaining 3-5% we call exceptions. These you will have to memorize.

21. Chemical Nomenclature Key Concepts to Master Nomenclature –All Compounds (Molecules) are neutral. –Learn the tables of monoatomic & polyatomic ions in chapter 3.

23. Chemical Nomenclature Naming Binary Ionic Compounds –Name the metal cation as it appears in the table. –Name the nonmetal anion as it appears in the table but substitute the ending –ide to the name. –No Greek prefixes for binary ionic compounds

27. Chemical Nomenclature NaCl KF CaO MgBr 2 sodium chloride potassium fluoride calcium oxide magnesium bromide

28. Chemical Nomenclature Naming Binary Ionic Compounds that contain a Transition Metal –Name the metal cation as it appears in the table. –Write the charge of the metal cation as a Roman numeral in parenthesis () following the cation name. –Name the nonmetal anion as it appears in the table but substitute the ending –ide to the name

32. Chemical Nomenclature Naming Binary Ionic Compounds that contain a Transition Metal –Sometimes you will still see the “older” system for naming. –Need to remember that the higher charge (valence) on metal cation takes the –ic ending. –The lower charge takes the –ous ending. –Memorize the tables of ions (names, formulas, charges).

33. Chemical Nomenclature FeCl 2 FeCl 3 iron (II) chloride (ferrous chloride) iron (III) chloride (ferric chloride)

34. Chemical Nomenclature Naming Ionic Compounds that Contain Polyatomic Ions –Name the polyatomic ions the same way they appear in the table. –Need to know these guys.

36. Chemical Nomenclature NaNO 3 (NH 4 ) 2 SO 4 Sodium nitrate Ammonium sulfate