Nursing Elites

1. What is the mass number of an atom with 6 protons, 6 neutrons, and 6 electrons?

• A. 12
• B. 18
• C. 6
• D. 8

Correct answer: A

Rationale: The mass number of an atom is the sum of protons and neutrons. In this case, the atom has 6 protons and 6 neutrons, thus the mass number is 6 + 6 = 12. Therefore, choice A (12) is the correct answer. Choices B (18), C (6), and D (8) are incorrect because the mass number is determined by the sum of protons and neutrons, not the number of electrons or a different combination of particles.

2. What happens in a single displacement reaction?

• A. A compound decomposes into two substances.
• B. An active element displaces a less active element.
• C. A precipitate solid forms from the reaction of two solutions.
• D. The oxidation states of atoms in the reactants change.

Correct answer: B

Rationale: In a single displacement reaction, an active element displaces a less active element in a compound. This process involves one element replacing another in a compound, resulting in the formation of a new compound. Option A is incorrect because a single displacement reaction does not involve the decomposition of a compound into two substances. Option C is incorrect because it describes a precipitation reaction, not a single displacement reaction. Option D is incorrect because it describes oxidation-reduction reactions, not specifically single displacement reactions.

3. What charge do Group VIA elements typically have?

• A. -1
• B. -2
• C. -3
• D. 0

Correct answer: B

Rationale: Group VIA elements, also known as Group 16 elements, typically have a charge of -2. This is because they have 6 valence electrons and tend to gain 2 electrons to achieve a stable octet configuration, resulting in a -2 charge. Choice A (-1) is incorrect as Group VIA elements need to gain 2 electrons for stability, not just 1. Choice C (-3) is incorrect because Group VIA elements do not need to gain 3 electrons to achieve stability. Choice D (0) is incorrect as Group VIA elements need to gain electrons to reach a stable configuration, resulting in a negative charge.

4. Which element has the highest electronegativity?

• A. Fluorine
• B. Chlorine
• C. Nitrogen
• D. Oxygen

Correct answer: A

Rationale: Fluorine has the highest electronegativity among the elements listed. Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. Fluorine, being the most electronegative element on the periodic table, has the strongest ability to attract electrons towards itself compared to chlorine, nitrogen, and oxygen. Therefore, fluorine is the correct answer. Chlorine, nitrogen, and oxygen have lower electronegativities compared to fluorine, making them incorrect choices for the element with the highest electronegativity.

5. Which two elements are most alike in reactivity?

• A. He and H
• B. K and Ar
• C. Cl and P
• D. Ba and Mg

Correct answer: C

Rationale: Chlorine (Cl) and Phosphorus (P) are most alike in reactivity among the given pairs. Both elements are nonmetals and belong to Group 7 (halogens) and Group 15 (nitrogen group), respectively. They have similar electronic configurations and can form compounds by gaining or sharing electrons. Chlorine is highly reactive and can easily form ionic compounds, while phosphorus also shows a range of reactivity in its compounds. Choice A (He and H) is incorrect because helium (He) is a noble gas and hydrogen (H) is a nonmetal, so they are not similar in reactivity. Choice B (K and Ar) is incorrect as potassium (K) is a metal and argon (Ar) is a noble gas, having different reactivities. Choice D (Ba and Mg) is incorrect because barium (Ba) and magnesium (Mg) are both metals, but their reactivities differ due to their positions in the periodic table.

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