Class copy- do not write on this paper
LW:_______ Carbon Bonding
Problem: Why is carbon able to form so many important molecules in living things?
Background:
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A carbon atom has 4 valence electrons. The valence shell (the outermost shell of an
atom) wants to have 8 electrons in it. To fill its outer shell, carbon is very good at
sharing electrons. This sharing is called a COVALENT BOND.
A hydrogen atom has 1 valence electron and its valence shell can hold 2. Therefore,
it wants one more electron to fill its shell
Carbon and hydrogen can share electrons and join together to form long chains, called
hydrocarbons. These hydrocarbons form the backbone of many important molecules in living
organisms
Materials:
Toothpicks
2 colors of gumdrops
crayons/colored pencils
Rules:
You will need gumdrops of one color to represent carbon atoms and gumdrops of another color to
represent hydrogen atoms. The toothpicks represent the bond that forms between 2 atoms.
You must remember: EACH CARBON ATOM FORMS FOUR BONDS
EACH HYDROGEN FORMS ONE BOND
Procedure:
1. Use the rules listed ABOVE TO MAKE A MODEL OF CH4 (METHANE). DRAW AND LABEL THIS
MODEL IN YOUR NOTEBOOK
2. Make a model of C2H6. (ethane). Draw and label it in your notebook
3. Make a model of C3H8. ( propane). Draw and label it in you notebook
4. Make a model of C4h10 (butane). Draw and label it in your notebook
5. Make another model of C4h10 with a BRANCHED chain. SEE PAGE 300 IN YOUR TEXTBOOK.
Draw and label it in your notebook
6. Discuss with your lab partners: How many different structures can be formed from the chemical
formula C5H12. Build and draw as many different models of C5H12 (pentane) as you can.
ANALYSIS
1. What information does a structural formula give you that a chemical formula does not?
2.
Look at your Perioidic Table . Are there any other elements that are able to form 4 bonds? List
examples
CONCLUSION:
write a paragraph to explain why carbon plays such an important role in the chemistry of living
organisms. (hint, use pages 292 – 293 in your textbook)