Unit 4
Unit 4 (Chapter Five) Study Guide
1. Using the rectangle below to represent the periodic table, indicate the trend (increasing or
decreasing) for each of the following:
Atomic radius
Electron
affinity
Ionic radius
Electronegativity
Ionization
energy
2. When comparing an element at the top of group 16 with one at the bottom of the same group,
what would you know about each of the trends above?
3. Write an equation for the formation of a negative ion from atom A and indicating that the
reaction is exothermic.
4. Write an equation for the formation of a positive ion from atom A and indicating that the
reaction is endothermic.
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5. Write the electron configuration of an anion formed from chlorine.
6. Write the electron configuration of a cation formed from potassium.
7. What is a noble gas configuration?
8. What is meant by the term highly reactive (or active)?
9. Which elements are the most reactive nonmetals? Speculate on why this is the case.
10. Which elements are the most reactive metals? Speculate on why this is the case.
11. Which ion is most likely to form? (explain your choice) Mg3+
Ca+1 O2-
12. Explain why there should be a connection between an element’s electron configuration and
its location on the Periodic table.
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13. The electron affinity for lithium is calculated to be -61.8 kJ. Is this an endothermic or an
exothermic reaction? Explain your answer.
14. Use the spheres to answer these questions.
A.
B.
a. Which sphere would most likely represent a potassium atom?
b. Which shpere would most likely represent a potassium ion?
c. If the spheres represent an atom and an anion of the same element, which sphere represents the
atom and which represent the anion?
15. a. What is the trend for ionic radius across a period?
b. The radius of the ion P3- is much larger than that of Al3+ in the same period. Explain why this
is the case.
16. Explain each of the following comparisons.
a. Calcium has a smaller second ionization energy than does potassium.
b. Lithium has a larger first ionization energy thans does cesium.
c. Magnesium has a larger third ionization energy than does aluminum.
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17. Explain why it takes more energy to remove a 4s electron from zinc than from calcium.
18. Examine the following series of equations. What trend is demonstrated?
Li + 520 kJ/mol  Li+ + eO + 1314 kJ/mol  O+ + eF + 1681 kJ/mol  F+ + eNe + 2080 kJ/mol  Ne+ + e-
19. Atoms and ions with the same number of electrons are called isoelectronic.
a. Write the symbol for a cation and an anion that are isoelectronic with krypton.
b. Is it possible for a cation to be isoelectronic with an anion from the same period?
Explain.
20. a. Name a metal in Group 14.
b. Name one halogen.
c. What is the name of Group 1?
d. Name the nonmetal often included in Group 1.
21. For each question there are two statements. Decide whether each statement is true or false.
Then decide whether Statement II is a correct explanation for Statement I.
STATEMENT I
STATEMENT II
Electronegativity values are higher for
metals than for nonmetals.
Atoms of nonmetals are among the largest
atoms.
A calcium atom is larger than a calcium ion.
Ions are always larger than the atoms
from which they are formed.
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Unit 4
STATEMENT I
STATEMENT II
The element hydrogen is a metal.
Hydrogen is on the left in the periodic
table.
Among all the elements in a period, the
noble gas always has the smallest
Ionization energy.
Within any period, atomic radii tend to
decrease moving from right to left.
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22. The graphs show the relationship between the electronegativities
and first ionization energies for period 2 and period 3 elements.
a. Based on data for these two periods, what is the general trend
between these two values?
b. Use nuclear charge and shielding effect to explain this trend.
23. Suppose you were given an unidentified element and asked to find a place for it on the
Periodic Table. How would you determine its approximate placement based on what you learned
in this unit?