Nursing Elites

1. How does the stability of an atom's nucleus influence its radioactive decay?

• A. Stable nuclei never undergo radioactive decay.
• B. Unstable nuclei are more likely to decay through various processes.
• C. Decay releases energy, making stable nuclei more prone to it.
• D. The element's position on the periodic table determines its decay rate.

Correct answer: B

Rationale: Unstable nuclei are more likely to decay through various processes. The stability of an atom's nucleus is a key factor in determining whether it will undergo radioactive decay. Unstable nuclei have an excess of either protons or neutrons, leading to an imbalance in the nucleus. To achieve a more stable configuration, these nuclei will undergo radioactive decay by emitting particles or energy. Stable nuclei, on the other hand, are less likely to undergo radioactive decay as they have a balanced number of protons and neutrons.

2. Which of the following reagents can be used to convert a primary alcohol to an alkyl halide?

• A. HI
• B. H2O
• C. NaOH
• D. SOCl2

Correct answer: D

Rationale: The correct answer is D: SOCl2. SOCl2, also known as thionyl chloride, is commonly used to convert primary alcohols to alkyl halides through an SN2 mechanism. Thionyl chloride reacts with the alcohol to form an alkyl chloride, replacing the hydroxyl group. Option A, HI (hydroiodic acid), is typically used to convert alcohols to alkyl iodides, while option B, H2O (water), and option C, NaOH (sodium hydroxide), are not reagents suitable for this specific transformation. Therefore, SOCl2 is the most appropriate reagent for converting a primary alcohol to an alkyl halide.

3. Which gland located in the neck is responsible for regulating metabolism, growth, and development?

• A. Parathyroid gland
• B. Thyroid gland
• C. Pituitary gland
• D. Thymus gland

Correct answer: B

Rationale: The correct answer is B: Thyroid gland. The thyroid gland is located in the neck and plays a crucial role in regulating metabolism, growth, and development. It produces hormones such as thyroxine (T4) and triiodothyronine (T3) that control the body's metabolic rate, affecting energy levels and growth. The parathyroid gland (A) regulates calcium levels in the body, the pituitary gland (C) controls several other glands and their hormone production, and the thymus gland (D) is involved in the immune system's development. Therefore, the thyroid gland is the most appropriate choice for the functions described in the question.

4. A keystone species plays a critical role in an ecosystem because its removal would:

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Rationale: Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. They play a critical role in maintaining the structure and function of an ecosystem. If a keystone species is removed from an ecosystem, it can disrupt the food web by causing imbalances in predator-prey relationships. This disruption can lead to cascading effects on other populations within the ecosystem, potentially causing population declines or even extinctions. Therefore, the removal of a keystone species would have significant impacts on the overall ecosystem structure, making option D the correct answer.

5. Which statement is TRUE about valence electrons?

• A. They are located in the innermost electron shell.
• B. They have the highest binding energy to the nucleus.
• C. They are most likely to participate in chemical bonding.
• D. They have no influence on the element's chemical properties.

Correct answer: C

Rationale: They are most likely to participate in chemical bonding - Valence electrons occupy the outermost shell and are readily involved in forming bonds with other atoms.

6. A substance that can donate a hydroxide ion (OH-) in solution is classified as a:

• A. Salt
• B. Base
• C. Neutral compound
• D. Dehydrating agent

Correct answer: B

Rationale: Bases accept protons (H+) and can donate hydroxide ions

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