Question

1. which of the following is a pseudo-noble-gas electron configuration?

a. \\(1s^2 2s^2 2p^6 3s^2 3d^6\\)
b. \\(1s^2 2s^2 2p^6 3s^2 3p^6\\)
c. \\(1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10}\\)
d. \\(1s^2 2s^2 2p^6 3s^2 3d^{10} 4s^2\\)

1. how many electrons does nitrogen gain in order to achieve a noble-gas electron configuration?

a. 1
b. 2
c. 3
d. 4

1. how does oxygen obey the octet rule when reacting to form compounds?

a. it gains electrons.
b. it gives up electrons.
c. it does not change its number of electrons.
d. oxygen does not obey the octet rule.

1. the electron configuration of a fluoride ion, \\(\text{f}^-\\), is _______

a. \\(1s^2 2s^2 2p^5\\)
b. the same as that of a neon atom
c. \\(1s^2 2s^2 2p^6 3s^1\\)
d. the same as that of a potassium ion

1. what is the charge on the cation in the ionic compound sodium sulfide?

a. 0
b. 1+
c. 2+
d. 3+

1. how many valence electrons are transferred from the nitrogen atom to potassium in the formation of the compound potassium nitride?

a. 0
b. 1
c. 2
d. 3

1. what is the formula for sodium sulfate?

a. \\(\text{naso}_4\\)
b. \\(\text{na}_2\text{so}_4\\)
c. \\(\text{na}(\text{so}_4)_2\\)
d. \\(\text{na}_2(\text{so}_4)_2\\)

Explanation:

Identify pseudo-noble-gas configuration

Using the Pseudo-Noble-Gas Configuration knowledge point

$$
LATEXBLOCK0
$$

Determine nitrogen electron gain

Using the Valence Electron Shells knowledge point

$$
LATEXBLOCK1
$$

Analyze oxygen octet rule behavior

Oxygen is in Group 16 and has 6 valence electrons (\(2s^2 2p^4\)). To satisfy the octet rule and achieve a stable noble-gas configuration (\(2s^2 2p^6\)), it must gain 2 electrons. Therefore, oxygen obeys the octet rule by gaining electrons.

Determine fluoride ion configuration

The fluorine atom has 9 electrons (\(1s^2 2s^2 2p^5\)). The fluoride ion (\(\text{F}^-\)) gains 1 electron, resulting in 10 electrons with the configuration \(1s^2 2s^2 2p^6\). This is identical to the electron configuration of a neutral neon atom (\(\text{Ne}\)).

Determine sodium sulfide cation charge

Using the Ionic Charge Limits knowledge point

$$
LATEXBLOCK2
$$

Determine electron transfer in potassium nitride

Potassium (\(\text{K}\)) is a metal that loses electrons, while nitrogen (\(\text{N}\)) is a nonmetal that gains electrons. In the formation of potassium nitride (\(\text{K}_3\text{N}\)), valence electrons are transferred from potassium atoms to the nitrogen atom, not from nitrogen to potassium. Therefore, 0 valence electrons are transferred from nitrogen to potassium.

Determine formula for sodium sulfate

Sodium forms a \(\text{Na}^+\) cation. Sulfate is a polyatomic anion with the formula \(\text{SO}_4^{2-}\). To form a neutral ionic compound, two \(\text{Na}^+\) ions are required to balance one \(\text{SO}_4^{2-}\) ion, yielding the chemical formula \(\text{Na}_2\text{SO}_4\).

Answer:

Question 50

• a. \(1s^2 2s^2 2p^6 3s^2 3d^6\)
• b. \(1s^2 2s^2 2p^6 3s^2 3p^6\)
• c. \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10}\) (Correct answer)
• d. \(1s^2 2s^2 2p^6 3s^2 3d^{10} 4s^2\)

Question 51

• a. 1
• b. 2
• c. 3 (Correct answer)
• d. 4

Question 52

• a. It gains electrons. (Correct answer)
• b. It gives up electrons.
• c. It does not change its number of electrons.
• d. Oxygen does not obey the octet rule.

Question 53

• a. \(1s^2 2s^2 2p^5\)
• b. the same as that of a neon atom (Correct answer)
• c. \(1s^2 2s^2 2p^6 3s^1\)
• d. the same as that of a potassium ion

Question 54

• a. 0
• b. 1+ (Correct answer)
• c. 2+
• d. 3+

Question 55

• a. 0 (Correct answer)
• b. 1
• c. 2
• d. 3

Question 56

• a. \(\text{NaSO}_4\)
• b. \(\text{Na}_2\text{SO}_4\) (Correct answer)
• c. \(\text{Na(SO}_4)_2\)
• d. \(\text{Na}_2\text{(SO}_4)_2\)