NAME__________________________________________DATE_______________
Chapter 2 Review and Key Concepts
This Chapter is mostly review from your AMAZING chemistry class last year. You are
expected to read the chapter as you complete this handout.
Guided Reading
Concept 2.1: Matter consists of chemical elements in pure form and in combinations called compounds
1. Review the following terms. Define them if needed, however you will be responsible for knowing
and applying these terms in the future.
 matter
 element
 compound
2. What four elements make up 96% of all living matter? ______, ______, _______, _______
3. What is the difference between an essential element and a trace element?
Term
Definition
Examples
Essential element
Trace element
Concept 2.2: An element’s properties depend on the structure of its atoms
4. Here are some more terms that you should firmly grasp. Define each term.
 neutron
 atomic number
 proton
 atomic mass
 electron
 isotope
5. What is potential energy? Explain which has more potential energy in each pair:
a. electron in the first energy shell/electron in the third energy shell


electron shells
energy
b. water/glucose
6. What determines the chemical behavior of an atom?
Concept 2.3: The formation and function of molecules depend on chemical bonding between atoms
7. Here are some more terms that you should firmly grasp. Define each term if needed.
 covalent bond
 nonpolar covalent
 cation
bond
 ionic bond
 anion
 polar covalent bond
 valence electrons
 van der Waals
 ion
interactions
 electronegativity
8. Explain the difference between a nonpolar covalent bond and a polar covalent bond.
9. Make an electron distribution diagram of water. Which element is most electronegative? Why is water
considered a polar molecule? Label the regions that are more positive or more negative. (This is a very important
concept. Spend some time with this one!)
10. Explain van der Waals interactions. Though they represent very weak attractions, when these interactions are
numerous they can stick a gecko to the ceiling!
11. Here is a list of the types of bonds and interactions discussed in this section. Place them in order from the
strongest to the weakest: hydrogen bonds, van der Waals interactions, covalent bonds, ionic bonds.
12. Use morphine and endorphins as examples to explain why molecular shape is crucial in biology.
Modified from Pedersen (2014)
Concept 2.4: Chemical reactions make and break chemical bonds
13. Write the chemical shorthand equation for photosynthesis. Label the reactants and the products.
14. What is meant by dynamic equilibrium? Does this imply equal concentrations of each reactant and product?
Testing Your Knowledge -Self Quiz Answers
1._____
2._____
3._____
4._____
5._____
6._____
7._____
8._____
Write About It –
1. The percentages of naturally occurring elements making up the human body are similar to the percentages of those
elements found in other organisms. How would an evolutionary biologist explain and account for this similarity among
organisms? Your readings from Your Inner Fish can assist you in answering this question.
2. Female silkworm moths attract males by emitting chemical signals that spread through the air. A male hundreds of
meters away can detect these molecules and fly toward their source. The sensory organs responsible for this behavior
are their comb-like antennae. Each filament of an antenna is equipped with thousands of receptor cells that detect the
sex attractant. Based on what you learned in this chapter, create a testable hypothesis to account for the ability of the
male moth to detect a specific molecule in the presence of many other molecules in the air. What predictions does your
hypothesis make?
3. Using your knowledge of electron distribution, bonding and the theme of emergent properties write a response to
counter the following claim: “Its’ paranoid and ignorant to worry about industry or agriculture contaminating the
environment with their chemical wastes. After all, this stuff is just made of the same atoms that were already present in
our environment.”
Modified from Pedersen (2014)