Nursing Elites

1. Which of the following neurotransmitters slows down the activity of neurons, preventing them from becoming overexcited?

• A. Acetylcholine
• B. Dopamine
• C. GABA
• D. Serotonin

Correct answer: C

Rationale: The correct answer is C: GABA (gamma-aminobutyric acid). GABA acts as an inhibitory neurotransmitter that reduces neuronal activity, thus preventing overexcitation. Acetylcholine (choice A) is involved in muscle control and cognitive function, but it is not primarily responsible for slowing down neuronal activity. Dopamine (choice B) plays a role in reward-motivated behavior and motor control, rather than inhibiting neuronal firing. Serotonin (choice D) is involved in mood regulation, sleep, and appetite but does not primarily slow down neuronal activity to prevent overexcitation.

2. Which type of chemical reaction produces a salt?

• A. An oxidation reaction
• B. A neutralization reaction
• C. A synthesis reaction
• D. A decomposition reaction

Correct answer: B

Rationale: The correct answer is B, a neutralization reaction. In a neutralization reaction, an acid and a base react to produce a salt and water. This process involves the combination of H+ ions from the acid and OH- ions from the base to form water, while the remaining ions combine to form a salt. Therefore, a neutralization reaction is the specific type of chemical reaction that produces a salt. Choices A, C, and D are incorrect. An oxidation reaction involves the loss of electrons, a synthesis reaction involves the formation of a compound from simpler substances, and a decomposition reaction involves the breakdown of a compound into simpler substances. None of these reactions directly lead to the production of a salt, making them incorrect choices in this context.

3. When a blockage forms in a coronary artery, reducing blood flow to the heart muscle, this condition is called:

• A. Atherosclerosis
• B. Myocardial infarction
• C. Angina pectoris
• D. Heart murmur

Correct answer: B

Rationale: A myocardial infarction, commonly known as a heart attack, occurs when a blockage forms in a coronary artery, leading to reduced blood flow to the heart muscle. Atherosclerosis refers to the buildup of plaque in the arteries, which can lead to blockages but is not the name for this specific condition. Angina pectoris is chest pain or discomfort due to inadequate blood supply to the heart muscle, which is a precursor to a heart attack but not the name for this condition. A heart murmur is an abnormal sound heard during a heartbeat, often due to turbulent blood flow, and is not related to a blockage in a coronary artery.

4. Which element has the lowest electronegativity value?

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

Correct answer: C

Rationale: The correct answer is Helium (C). Electronegativity is the tendency of an atom to attract electrons towards itself in a bond. Helium, as a noble gas, has a very low electronegativity because its outer electron shell is already full and stable, resulting in minimal attraction for additional electrons. Oxygen (A), Fluorine (B), and Chlorine (D) are all non-noble gas elements that have higher electronegativity values compared to Helium due to their electron configurations and tendencies to attract electrons.

5. Which statement accurately describes the periodic trends in atomic radius?

• A. Increases down a group and decreases across a period
• B. Decreases down a group and increases across a period
• C. Remains constant throughout the table
• D. Fluctuates unpredictably based on individual elements

Correct answer: A

Rationale: The correct statement is that atomic radius increases down a group and decreases across a period. When moving down a group, additional electron shells increase the distance from the nucleus, leading to larger atomic radii. On the other hand, when moving across a period, the number of electron shells remains constant, but the increasing nuclear charge pulls electrons closer, resulting in smaller radii. Choice B is incorrect because atomic radius does not decrease down a group and increase across a period. Choice C is incorrect because atomic radius does not remain constant; it exhibits specific trends. Choice D is incorrect because atomic radius follows predictable trends based on the periodic table structure, rather than fluctuating unpredictably.

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