1. Molecular Compounds

2. When non-metals combine, a pure substance called a molecule or a molecular compound is formed  Composed of two non-metals  Can be solids, liquids, or gases at room temperature  Insulators  Low melting / boiling point (because forces between molecules are weak)

3. Writing Formulas for Molecular Compounds  DO NOT combine using ionic charge  Use subscripts to indicate the number of atoms present

4. Naming of Molecular Compounds 1.The first element in the compound uses the element name – just like ionic compounds 2. The second element in the compound has the suffix “ide”

5. 3. When there is more than one atom in the formula, a prefix is used which specifies the number of atoms. Number of AtomsPrefix 1mono 2di 3tri 4tetra 5penta 4. An exception to rule 3 is when the first element has only one atom; mono is not used

6. Molecular compounds are named using this format: Prefix + First Element Prefix + Second Element (with “ide” ending) CO 2 N2ON2O N2O3N2O3 NF 3 CCl 4 PF 5 Carbon Dioxide Dinitrogen monoxide Dinitrogen trioxide Nitrogen trifluoride Carbon tetrachloride Phosphourus Pentafluoride Elements Carbon ; oxygen Nitrogen ; oxygen Nitrogen ; fluorine Carbon ; Chlorine Phosphourus ; Fluorine

7. Write the Chemical Formula for the following molecular Compounds Dinitrogen trioxide Carbon Tetrachloride Phosphorus Pentachloride Carbon disulfide Sulfur trioxide N2O3N2O3 CO 4 PCl 5 CS 2 SO 3