MOLECULAR MODEL LAB

Name & Formula	Electro- negativity Difference	Bond Polarity	Drawing of Model	Lewis Structure	Symmetry (Yes/No)	Molecular Polarity	Molecular Shape
hydrogen H2
methane CH4
ammonia NH3
hydrogen bromide HBr
chloro- methane CH3Cl
oxygen O2
water H2O
carbon dioxide CO2
form- aldehyde CH2O
phosphorus trichloride PCl3

MOLECULAR MODEL KEY:
HYDROGEN = YELLOW NITROGEN = BLUE CHLORINE = GREEN
PHOSPHORUS = BLUE CARBON = BLACK                      BROMINE = ORANGE
OXYGEN = RED
WOODEN STICKS = SINGLE BONDS                            METAL SPRINGS = DOUBLE BONDS

QUESTIONS:

1.) What shapes of molecules ALWAYS yield polar molecules? Why?

2.) Explain why H₂O is polar and CO₂ is not. Use Lewis structures to answer.

3.) What kind of molecular polarity do you have if the molecule contains only nonpolar bonds? Why?

4.) What shapes are nonpolar molecules? Are these shapes ALWAYS nonpolar molecules? If not, give two examples (chemical formulas) when
these shapes are polar molecules.

5.) Explain why chloromethane is not symmetrical and polar. Also, explain why methane is symmetrical and nonpolar. Use Lewis structures to
answer.

6.) Fill in the blanks with either “symmetrical” or “not symmetrical”.
* Polar molecules are __________________________.
* Nonpolar molecules are __________________________.

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