Nursing Elites

1. Aluminum (Al) has 13 protons in its nucleus. What is the number of electrons in an Al3+ ion?

• A. 16
• B. 13
• C. 10
• D. 3

Correct answer: C

Rationale: Aluminum (Al) has an atomic number of 13, which indicates it normally has 13 electrons to balance the 13 protons in its nucleus. When Al forms an Al3+ ion, it loses 3 electrons to achieve a stable electron configuration. Therefore, the Al3+ ion will have 13 - 3 = 10 electrons. Choice A (16) is incorrect as it doesn't take into account the charge of the Al3+ ion. Choice B (13) is incorrect because the Al3+ ion has lost electrons. Choice D (3) is incorrect as it doesn't reflect the total number of electrons lost by the Al atom to form the Al3+ ion.

2. What is the oxidation state of the chlorine atom in the compound HCl?

• A. +1
• B. -1
• C. +2
• D. -2

Correct answer: B

Rationale: In the compound HCl (hydrochloric acid), the hydrogen atom has an oxidation state of +1 based on the rules of assigning oxidation states. Since the overall compound is neutral, the oxidation state of chlorine must be -1 to balance the charge. Chlorine typically has an oxidation state of -1 in binary compounds with nonmetals, such as HCl. Therefore, the correct answer is -1. Choices A, C, and D are incorrect as the oxidation state of chlorine in HCl is -1, not +1, +2, or -2.

3. Which of the following elements is a noble gas?

• A. Hydrogen
• B. Fluorine
• C. Argon
• D. Nitrogen

Correct answer: C

Rationale: The correct answer is C: Argon. Argon is a noble gas, part of Group 18 in the periodic table. Noble gases are colorless, odorless, and typically non-reactive under normal conditions. Other elements in this group include helium, neon, krypton, xenon, and radon. Argon finds wide applications in welding, lighting, and scientific research. Choices A, B, and D are not noble gases. Hydrogen is a non-metal, Fluorine is a halogen, and Nitrogen is a diatomic non-metal gas.

4. Here are the solubilities of four substances at 0°C, in grams of solute per 100 mL of water. If the temperature increases to 20°C, what would you expect to happen to the solubility figures?

• A. Citric acid and potassium phosphate will decrease; nitrogen and oxygen will increase.
• B. Citric acid and potassium phosphate will increase; nitrogen and oxygen will decrease.
• C. All four figures will increase.
• D. All four figures will decrease.

Correct answer: C

Rationale: Solubility generally tends to increase with temperature for most solid solutes in liquid solvents due to higher kinetic energy leading to better solute-solvent interactions. As the temperature increases from 0°C to 20°C, all four solubility figures are expected to increase. Choice A is incorrect because solubility tends to increase with temperature. Choice B is incorrect as well for the same reason. Choice D is incorrect because the solubility of solid solutes typically increases with temperature.

5. What is the correct name of AgNO₃?

• A. Argent nitrous
• B. Argent oxide
• C. Silver nitrite
• D. Silver nitrate

Correct answer: D

Rationale: The correct name for AgNO₃ is silver nitrate. In chemical nomenclature, the element symbol Ag represents silver, and the polyatomic ion NO₃ is known as nitrate. Therefore, when the silver ion (Ag⁺) combines with the nitrate ion (NO₃⁻), the resulting compound is named silver nitrate (AgNO₃). Choices A, B, and C are incorrect because they do not accurately represent the composition of AgNO₃. Argent nitrous (Choice A) and Argent oxide (Choice B) do not reflect the correct anion, and Silver nitrite (Choice C) uses a different anion altogether.

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