Chapter 2 Review
(Not to be turned in....this is for your review of the chapter's contents)

1. What is an element?
2. What is a compound?
3. What are the six most common elements found in living things?
4. Name the three subatomic particles their mass in Daltons and their charge.
5. What is the relationship between atomic number and protons?
6. What constitutes the mass number of an atom?
7. What is an isotope?
8. How are radioactive isotopes used in biological research?
9. Explain the relationship between energy and the position of the electron relative to the nucleus (its shell).
10. How many electrons may occupy an orbital?
11. What is a valence electron? What are the valences of each of the six most common elements?
12. Explain the term covalent bond. Differentiate between polar and nonpolar. What determines if a particular covalent bond is ploar or nonpolar?
13. What is an ionic bond? When an ionic salt disassociates in water it forms two types of ions. Give the names of both and identify the charge of each.
14. Characterize the hydrogen bond. It is between which atoms?
15. Why are weak bonds important in biology?
16. Compared to 31P, the radioactive isotope 32P has _________.
17. The atomic number of sulfer is 16. If sulfur combines with hydrogen to form a compund, predict the molecular formula for this molecule.
18. What coefficients must be placed in the blanks to balance this equation:

____H2O -----> ____ H2 + O2

19. An atom of phosphorus has an atomic number of 15. Based upon this information, what will be the distribution of electrons?
20. Which of the following factors is most significant when considering reactivity of an atom?
a. an atom is the smallest possible particle of an element
b. a molecule is the smallest possible part of a compound
c. a molecule consists of two or more atoms held together by interactions between their outermost electrons
d. the number of protons in the nucleus determines reactivity of an atom
21. What is a buffer?

Bruce Faitsch
Guilford High School
Guilford, CT