Nursing Elites

1. Electrons occupy specific energy levels around the nucleus, but not in fixed orbits. This concept is captured by the:

• A. Bohr model
• B. Quantum mechanical model
• C. Lewis structure
• D. Octet rule

Correct answer: B

Rationale: The correct answer is the Quantum mechanical model. Unlike the Bohr model with its defined electron paths, the quantum mechanical model uses probability distributions to describe electron locations within energy levels. Choice A, the Bohr model, describes fixed electron orbits, which is not in line with the concept of electron distribution in energy levels. Choices C and D, Lewis structure and Octet rule respectively, are not related to the description of electron distribution around the nucleus in energy levels, making them incorrect answers.

2. What information can be obtained from the mass number of an element?

• A. The number of protons in the nucleus
• B. The total number of protons and neutrons
• C. The number of electrons in the valence shell
• D. The element's chemical reactivity

Correct answer: B

Rationale: The mass number of an element represents the total number of protons and neutrons in the nucleus. This information is crucial for determining the atomic mass of the element and understanding its stability and isotopes. The number of protons in the nucleus (option A) is represented by the atomic number, not the mass number. The number of electrons in the valence shell (option C) is related to the element's position in the periodic table and its chemical properties, but it is not directly determined by the mass number. The element's chemical reactivity (option D) is influenced by the number and arrangement of electrons in the atom's energy levels, not by the mass number.

3. Which part of the brain is responsible for voluntary muscle movements?

• A. Medulla oblongata
• B. Cerebrum
• C. Hypothalamus
• D. Thalamus

Correct answer: B

Rationale: The question inquires about the brain region responsible for voluntary muscle movements. The correct answer is the Cerebrum. The cerebrum is the main part of the brain involved in voluntary muscle control and motor coordination. The Medulla oblongata is primarily responsible for regulating vital functions like breathing and heart rate, not voluntary muscle movements. The Hypothalamus plays a role in regulating body temperature, thirst, hunger, and other homeostatic processes. The Thalamus serves as a relay station for sensory information but is not directly responsible for voluntary muscle movements.

4. As a car accelerates from rest, what happens to its kinetic energy and the work done on it?

• A. Both kinetic energy and work done increase.
• B. Kinetic energy increases, but work done remains constant.
• C. Work done increases, but kinetic energy remains constant.
• D. Both kinetic energy and work done remain constant.

Correct answer: A

Rationale: When a car accelerates from rest, its speed and kinetic energy increase. The work done on the car is what increases its kinetic energy, so both kinetic energy and work done increase simultaneously. Option A is correct because acceleration results in an increase in both kinetic energy and the work done on the car. Option B is incorrect because work done is required to increase kinetic energy during acceleration. Option C is incorrect as work done is directly related to the change in kinetic energy. Option D is incorrect as both kinetic energy and work done increase when the car accelerates.

5. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

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