PROBLEM SET
Atomic Structure
These questions and activities come from a variety of sources: your textbook, other books that I have, study guides,
and old homeworks, labs, and exams. They are provided to give you an idea of the types of questions you can expect
to see on exams. These are not to be turned in for a grade, though I am happy to go over your answers with you.
Important Vocabulary Terms: Write out definitions for each of the following terms:
a. atom
b. element
c. proton (p+)
d. neutron (n0)
e. electron (e-)
f. atomic nucleus
g. electron shell (orbital)
h. valence electron
i. atomic number
j.
atomic mass
k. isotope
Multiple Choice: Select the best answer from the choices provided:
1. What does the term electron orbital describe?
A. An electron orbital describes the orbit of an electron around the nucleus.
B. An electron orbital describes the exact distance of an electron from the nucleus.
C. An electron orbital describes a three-dimensional space where an electron can be found
90% of the time.
2. In the term trace element, the adjective trace means that
A. the element can be used as a label to trace atoms through an organism's metabolism.
B. the element enhances health but is not essential for the organism's long-term survival.
C. the element is very rare on Earth.
D. the element is required in very small amounts.
E. the element passes rapidly through the organism.
3. Compared with 31P, the radioactive isotope 32P has
A. a different atomic number.
B. a different charge.
C. one more neutron.
D. one more proton.
E. one more electron.
4. We can represent atoms by listing the number of protons, neutrons, and electrons—for
example, 2p+, 2n0, 2e- for helium. Which of the following represents the 18O isotope of
oxygen?
A. 6p+, 8n0, 6eB. 7p+, 2n0, 9eC. 10p+, 8n0, 9eD. 9p+, 9n0, 9eE. 8p+, 10n0, 8e-
Fill-in-the-blank. Complete each blank with the one best answer.
1. The difference between the mass number and the atomic number of an atom is equal to the
number of _________________. An atom of phosphorus, 3115P, contains ______ protons,
______ electrons, and ______ neutrons.
2. To move to a shell farther from the nucleus, an electron must _________________ energy;
energy is _________________ when an electron moves to a closer shell.
Additional problems: Write your answers in the spaces provided.
1. Review the discussion of emergent properties (either in Introduction to Biology or on p. 3 of
the textbook). Explain how table salt has emergent properties.
2. Use Fig. 2.9 (p. 36) in the text or your Periodic Table to complete the table below.
Symbol
Name
Symbol
P
helium
carbon
S
Name
N
potassium
3. Table 2.1 (right) lists the chemical elements that
occur naturally in the human body, but the
numbers are similar for other living organisms.
•
In what non-living chemical forms are these
elements often found as in nature? (Look out
your window.)
•
How do animals obtain these elements from
their environments?
•
How do plants obtain these elements from
their environments?
4. In humans, iron is a trace element required for the proper functioning of hemoglobin, the
molecule that carries oxygen in red blood cells. What might be the effects of an iron
deficiency?
5. Fill in the following chart for the major subatomic particles of an atom.
Particle
Charge
Mass
Location
6. How many electrons does fluorine have? How many electron shells? How many electrons are
needed to fill fluorine's outermost electron shell?
7. If two or more elements are in the same row on the Periodic Table, what do they have in
common? What about if two elements are in the same column? What does that mean?
8. The percentages of naturally occurring elements making up the human body are similar to the
percentages of these elements found in other organisms. How do you account for this
similarity among organisms?
9. Atoms can have various numbers associated with them. Complete the table below. Please use
your periodic table. Feel free to round any decimals.
element
atomic #
mass #
# protons
# electrons
# neutrons
carbon (C)
fluorine (F)
neon (Ne)
osmium (Os)
tungsten (W)
iodine (I)
10. List the maximum number of electrons that can be found in the first three electron shells. (By
the way, what is the minimum number of electrons in an electron shell? Hint: it’s not zero.)
11. Where are valence electrons found in an atom? Why does their location make them different
from the other (non-valence) electrons?
12. In the lab, you are studying an element composed of atoms with 14 protons.
•
What element are you studying?
•
How many electrons would an atom of this element contain?
•
How many empty spaces would you expect to find in its outermost electron shell?
13. Circle the pair of atoms that you would expect to behave similarly, based on their numbers of
valence electrons:
•
fluorine (F) and oxygen (O)
•
hydrogen (H) and helium (He)
•
neon (Ne) and sodium (Na)
•
oxygen (O) and sulfur (S)
14. An atom with a completed valence shell, like neon, is inert or chemically nonreactive. List
two more examples of inert atoms from the table: ___________ & ___________
15. Fill in the blanks in the following concept map to help you review the atomic structure of
atoms.
16. Drawing atoms. In the space below, draw out each of the following atoms. You should put
the appropriate number of protons and neutrons in its nucleus, and the correct number of
electrons (in their electron shells). Empty spaces can be omitted or left as empty circles (O).
Carbon (C):
Oxygen (O):
Hydrogen (H):
Fluorine (F):
Sodium (Na):
Chlorine (Cl):