1. Aim: What are molecular compounds? DO NOW: 1. COMPARE AND CONTRAST METALLIC BONDING AND IONIC BONDING. 2. WHAT WOULD BE THE IONIC CHARGE FOR AN ATOM WITH THIS LEWIS DOT STRUCTURE? X Y

2. Ionic Compounds Review  In Ionic Bonding electrons are being transferred (“given up” or “stolen away”)  Occurs between a metal and a nonmetal resulting in the formation of a salt

3. Molecular Compounds  The atoms in molecular compounds are held together by covalent bonds  Covalent bonds are the sharing of electrons between nonmetals.

5. Molecule  A molecule is a neutral group of atoms joined together by covalent bonds  Diatomic molecules- two atoms, either of the same or different element) are joined together by a covalent bond  Ex: H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2  HCl

6. Salt vs Molecules  A salt is a metal cation and a nonmetal anion joined together by an ionic bond  A molecule is a group of atoms joined together by a covalent bond  A compound is a group of two or more elements bonded together (ionic or covalent)

7. Covalent Bond vs Ionic Bond

8. Properties of Molecular Compounds  Mostly liquid or gases at room temperature  Lower melting points than ionic compounds (meaning the bonds are weaker than ionic bonds)

9. Molecular Formulas  The molecular formula is the formula of a molecular compound  It shows how many atoms of each element a molecule contains  Ex: H 2 O contains 3 atoms (2 atoms of H, 1 atom of O)  C 2 H 6 contains 8 atoms (2 atoms of C, 6 atoms of H)

10. Ionic vs. Covalent IONICCOVALENT Bonded NameSaltMolecule Bonding TypeTransfer e - Share e - Types of ElementsMetal & Nonmetal Nonmetals Physical StateSolid Solid, Liquid, or Gas Melting Point High (above 300ºC)Low (below 300 ºC) Solubility Dissolves in Water Varies ConductivityGoodPoor

11. Practice How many atoms total and of each do the following molecular compounds contain? 1. H 2 2. CO 3. CO 2 4. NH 3 5. C 2 H 6 O

12. Practice: True or False 1. All molecular compounds are composed of atoms of two or more elements. 2. All compounds are molecules. 3. Molecular compounds are composed of two or more nonmetals. 4. Atoms in molecular compounds exchange electrons. 5. Molecular compounds have higher melting and boiling points than ionic compounds.