Naming Compounds 10/01/2015

Warm Up  How does Lithium and Phosphorous combine to form an ionic compound?

Schedule  Warm Up  Naming Ionic Compounds  Covalent Bonds - Fruit Loop Activity  Work Time  Homework:  Nomenclature of Ionic and Covalent Compounds Worksheet- Due Friday October 2 nd  Vocabulary- Due October 2 nd  Test/Lab Corrections- Due October 2 nd  Vocabulary Quiz Tomorrow!

What does a subscript and a superscript tell us ?  Subscripts: How many atoms are in a compound  Example: S 2  Superscripts: Tell us the charge on an element  Example: S 2+

How do we Write a Chemical Formula for an ionic compound?  1) We need to look at the charges for the two elements combining  2) Look at Lithium and Fluorine. What are their charges?

Write these ions with their charges. Then use the Crossing Over Rule Li 1+ Cl 1- Li 1 Cl 1 New Compound: LiCl The charges cancel each other out if they are similar

Examples

How do we name Ionic Compounds? 1. W rite the name of the metal first  Example: Lithium 2. Follow it with the name of the nonmetal  Example: Lithium Chlorine 3. Add the suffix "ide" to the end of the nonmetal  Example: Lithium Chloride  These are binary compounds because they only contain two elements

Polyatomic Ions and how we name them  Not all ionic compounds are binary compounds. Some ionic compounds are form by using both ionic bonding and covalent bonding. binary compoundscovalent bonding  The resulting ion contains a charge, because the total number of electrons from the set of atoms cannot produce a stable structure.  Some Examples of Polyatomic Ions:

Covalent Bonding and how we name these bonds  A Covalent Bond is when two elements share electrons  The Lewis structure of a fluorine atom shows that each fluorine atom has seven valence electrons.  Make this Fluorine atom with your Fruit Loops

Covalent Bond  A fluorine atom needs one more electron to be happy.  If a fluorine atom shares one of its electrons with another fluorine atom, the valence shells of both atoms become filled. The two shared electrons form a single bond between the atoms.single bond  A line can be used to represent the shared electron pair.

Now Write the Chemical Formula for this Covalent Bond on this slide F Now try Hydrogen + Oxygen

Fruit Loop Activity  Pass out Bags with Fruit Loops and Letters  Pass out Worksheet  We will make these Covalent Bonds as a class – follow my directions on the Document Camera

Naming Covalent Bonds or Molecular Compounds  If a chemical formula is given, the first element in the formula is named first.  To describe the number of atoms of each element in a molecule, the chemical nomenclature uses Greek prefixes.moleculenomenclature

Example H 2 S Name: dihydrogen monosulfide

Empirical Formula vs. Molecular Formula  The formula of a compound expressed as the smallest possible whole- number ratio of subscripts of the elements in the formula  For example, CH 3 COOH has two carbons, four hydrogens and two oxygens. So we could write the formula like this: C 2 H 4 O 2 and so it reduces to CH 2 O.