Question 1

Which of the following best explains why the first ionization energy generally increases across a period from left to right in the periodic table?

Accepted Answer

The number of protons increases, resulting in a greater effective nuclear charge, which pulls electrons closer to the nucleus.

Question 2

Which of the following elements would you expect to have the largest second ionization energy?

Accepted Answer

Na

Question 3

Which equation correctly represents the first ionization energy of magnesium?

Accepted Answer

$$ \mathrm{Mg}(g) \rightarrow \mathrm{Mg}^+(g) + e^- $$

Question 4

Which of the following best describes the trend in atomic radius as you move down a group in the periodic table?

Accepted Answer

Atomic radius increases due to the addition of electron shells.

Question 5

Which of the following ions has the smallest radius?

Accepted Answer

$$ \mathrm{Na}^+ $$

Question 6

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity is the energy change when an electron is added to a neutral atom in the gas phase.

Question 7

Which of the following best explains why chlorine has a higher (more negative) electron affinity than sodium?

Accepted Answer

Chlorine has a greater effective nuclear charge and is closer to achieving a full octet.

Question 8

Which of the following correctly describes the Born-Haber cycle for the formation of NaCl(s)?

Accepted Answer

It involves sublimation of Na(s), ionization of Na(g), dissociation of Cl$$_2(g$$), electron affinity of Cl(g), and formation of NaCl(s) from gaseous ions.

Question 9

Given the following steps in the Born-Haber cycle for NaCl, which step corresponds to the lattice energy?

Accepted Answer

$$ \mathrm{Na}^+(g) + \mathrm{Cl}^-(g) \rightarrow \mathrm{NaCl}(s) $$

Question 10

Which of the following equations correctly represents Coulomb's Law for lattice energy?

Accepted Answer

$$ E = \dfrac{k Q_1$ Q_2$}{r} $$

Question 11

Which of the following pairs of ions would produce the largest (most negative) lattice energy according to Coulomb's Law?

Accepted Answer

$$ \mathrm{Mg}^{2+} $$ and $$ \mathrm{O}^{2-} $$

Question 12

Which of the following best explains why the formation of ionic bonds is generally exothermic?

Accepted Answer

The lattice energy released when oppositely charged ions come together is greater than the energy required to form the ions.

Question 13

Which of the following is a correct statement about the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve a noble gas electron configuration.

Question 14

Which of the following best describes the change in energy when a neutral atom gains an electron?

Accepted Answer

The process is called electron affinity and is usually exothermic for nonmetals.

Question 15

Which of the following best explains why the second ionization energy of sodium is much higher than the first?

Accepted Answer

The second electron is removed from a stable, noble gas configuration, requiring much more energy.

Question 16

Which of the following best describes the trend in ionic radii for isoelectronic species (ions with the same number of electrons)?

Accepted Answer

As the nuclear charge increases, the ionic radius decreases.

Question 17

A patient is given a salt containing $$ \mathrm{Ca}^{2+} $$ and $$ \mathrm{F}^- . $$Which of the following best describes the expected lattice energy of this salt compared to $$ \mathrm{NaCl} $$?

Accepted Answer

It will be more negative (larger in magnitude) because both ions have higher charges.

Question 18

Which of the following is NOT a step in the Born-Haber cycle for the formation of $$ \mathrm{KBr}(s) $$?

Accepted Answer

Hydration of $$ \mathrm{K}^+ $$ and $$ \mathrm{Br}^- $$ ions.

Atomic Structure, Periodic Trends, and Ionic Compounds: Study Notes

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