The Bare Essentials of Polarity

Answer Key

1. How does the comic book define a “polar molecule?”

A molecule with a difference in electrical charge between two ends.

2. Define electronegativity as you understand it, after reading the first two pages of the comic book.

Electronegativity (EN) is the ability of an atom/nucleus to attract bonding electrons toward itself.

3. Interpret the picture at the bottom of page 1. Explain how the iceberg, penguins, and polar bears represent trends in electronegativity.

Iceberg = periodic table Polar bears = more electronegative atoms (the larger the polar bears, the more electronegative) Penguins = less electronegative atoms (the smaller the penguins, the less electronegative)

4. What is the artist trying to represent when there are two polar bears arm wrestling together, or two penguins arm wrestling together?

They are equal in EN, so they pull electrons equally and neither one will have more electrons than the other one.

5. a) What three types of bonds are represented on page 3 of the comic book? 1) Nonpolar covalent 2) Polar covalent 3) Ionic

5. b) What happens to the bonding electrons in each type of bond?

1) Nonpolar covalent – electrons (ice cream cones) are shared equally 2) Polar covalent – the more electronegative atom(polar bear) hogs more electrons (ice cream) than the less electronegative atom (penguins) 3) Ionic – the more electronegative atom (polar bear) completely steals the electrons (ice cream) and the less electronegative atom (penguin) does not get any.

6. Explain why there are four scoops of ice cream in the illustration of O 2 on page 3.

Each scoop means one electron. Since oxygen atoms share a double bond, they share a total of four electrons (ice cream scoops)

7. What do the six scoops of ice cream represent in the illustration of N 2 on page 4?

Each scoop means one electron. Since nitrogen atoms share a triple bond, they share a total of six electrons (ice cream scoops)

8. Describe what you think is happening to the penguin in the CO 2 molecule in the picture on page 4.

The two oxygen atoms (polar bears) are more electronegative and hog the electrons (ice cream), but the carbon atom (penguin) is sharing with both, so it gets a fair share of electrons (ice cream)

9. Name three things that the picture of CO 2 page 4 illustrates about the molecule.

on 1. Atoms in the molecule 2. Relative EN of each atom 3. Number of bonds (electrons) between each atom

10. Describe what you think is happening to the penguins in the illustration of H 2 O on page 4.

They don’t get an equal share of electrons (ice cream)

11. Explain what you think the crossed arrow represents in the comic book. ↦ • Arrow = the direction the electrons (ice cream) are being pulled • Cross = a slightly positive charge on that side of the bond

12. What are the three definitions of “dipole” given in the comic book?

1) The polarity of an individual polar bond between atoms 2) The net polarity of a polar molecule that may have several polar covalent bonds within it 3) The polar molecule itself