Lab 2: Atoms, Molecules and Isomers

5 Points

NOTE: This lab is meant to reinforce the concepts from chapter 2 in your textbook. There will not be an associated PowerPoint or video with this lab. Use the lecture PowerPoint to guide you.

1. Use your knowledge of atomic structure to fill in the table below, based on the names and atomic numbers of elements provided.

Element

Atomic Number

Mass Number

Electron Distribution Diagram

Hydrogen

1

Carbon

6

Oxygen

8

Nitrogen

7

Chlorine

17

Sulfur

16

Phosphorus

15

2. Name two trace elements, and list one specific function in human cells for each of these.

a. Element: Function:

b. Element: Function:

3. Draw a Bohr (electron distribution) diagram for the following two isotopes of sulfur:

S-32 b. S-35

4. Build a model of propane (C3H8). Draw the structure and make some observations about this molecule below.

5. Return to your propane model. What type of bonds hold the carbon and hydrogen together? Even though propane is a gas that’s not found in cells, why might the kind of bonds found in propane be important in cell biology? Be specific.

In this section, we’re going to start looking at some larger organic (carbon-based) molecules.

6. Draw the electron distribution model for carbon:

7. How many valence electrons does carbon have?

8. How many covalent bonds will carbon form?

9. What kinds of variations are found in carbon-based structures? To explore this question, see how many different shapes you model using 6 carbons in 5 minutes. Use ONLY carbon atoms and single/double bond options as you build – you can assume the presence of non-carbon atoms such as hydrogen in all remaining positions. Draw these carbon skeletons in the space below.

In building various carbon structures, you likely built some isomers – molecules that have the same chemical formulas, but different arrangements of the atoms. In this next section, you will focus on a couple specific isomers.

10. Draw the two isomers of butane (C4H10). Are these cis-trans isomers, structural isomers, or enantiomers?

11. Draw the cis- and trans- forms of dichloroethene where the chemical formula is C2H2Cl2.