1. Covalent Bonds Understanding how oil and water can be made to mix together.

2. What are covalent bonds? ► Covalent bonds occur when two or more atoms come together and share an electrons. ► The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons. ► Examples of molecules with covalent bonds are NH 3, F 2, O 2, N 2, and CO 2.

3. Multiple bonds ► Double and triple bonds are common in covalent atoms. ► A bond between two atoms contains two electrons, and is represented by two dots between two elements. ► A double bond contains four electrons and produces two bonds. ► A triple bond contains six electrons and produces three bonds. ► Oxygen (O 2 ) has a double bond, while (N 2 ) has a triple bond.

4. Molecular compounds ► Molecules come together to produce a molecular compound. ► Compared to ionic compounds molecular compounds have lower melting points and boiling points. ► Molecular compounds also do not conduct electricity when dissolved in water or melted. (NaCl and water is an ionic combination by comparison).

5. Comparing molecular and ionic bonds SubstanceFormula Melting point (Degree C) boiling Methane CH 4 -184.4-161.5 Rubbing alcohol C3H8OC3H8OC3H8OC3H8O-89.582.4 Zinc chloride ZnCl 2 290732 Magnesium chloride MgCl 2 7141412

6. An unequal sharing of electrons ► In molecular compounds the electrons are not distributed equally through the molecule. ► The result is a molecule which has a slight charge to it as a entire molecule. ► The need to possess all of the atoms is similar to a game of tug of war, except the molecule is having this battle with itself.

7. Polar and nonpolar bonds. ► Polar covalent bonds occur when electrons are shared unevenly which produces a positive and a negative end of a molecules. (HF acid, and H 2 O are examples.) ► Water is the universal solvent ► Non polar covalent molecules occur when electrons are shared equally by the atoms in a molecule. (F 2, and CO 2 are examples)

8. Understanding how oil and water can mix. ► Water contains polar bonds and oil contains non polar bonds. ► Detergent is a large molecule which has a polar bond at one end and a non polar bond at the other. ► The detergent acts like a glue which binds both water and oil to itself on opposite ends in order to remove oil from a substance while being suspended in a water solution.