Nursing Elites

1. What is the main function of valence electrons in chemical bonding?

• A. They are responsible for holding the nucleus together.
• B. They are involved in forming bonds with other atoms.
• C. They determine the element's physical properties.
• D. They play no role in chemical reactions.

Correct answer: B

Rationale: Valence electrons are the electrons in the outermost energy level of an atom. These electrons are involved in forming bonds with other atoms, which is crucial for chemical bonding. By participating in bonding, valence electrons determine an atom's ability to form compounds and engage in chemical reactions. Therefore, the primary function of valence electrons is to facilitate the formation of bonds between atoms, making option B the correct answer. Choices A, C, and D are incorrect because valence electrons primarily influence chemical bonding by participating in the formation of bonds between atoms, rather than holding the nucleus together, determining physical properties, or having no role in chemical reactions.

2. Which of the following statements regarding the microscopic anatomy of heart muscle is correct?

• A. Cardiac muscle is striated, short, fat, branched, and interconnected
• B. Intercalated discs anchor cardiac cells together and allow the free passage of ions
• C. The connective tissue endomysium acts as both tendon and insertion
• D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' Cardiac muscle is indeed striated, short, fat, branched, and interconnected. Intercalated discs are responsible for anchoring cardiac cells together and allowing the free passage of ions. Additionally, the connective tissue endomysium provides structural support and acts as a tendon-like structure attaching muscle fibers to each other. Therefore, all the statements in choices A, B, and C are accurate when describing the microscopic anatomy of heart muscle. Choices A, B, and C individually represent different aspects of the structural features of cardiac muscle, making choice D the most comprehensive and correct answer.

3. Bone is primarily composed of which of the following inorganic materials?

• A. calcium
• B. magnesium
• C. collagen
• D. potassium

Correct answer: A

Rationale: Bone is primarily composed of calcium, making up about 70% of its inorganic content. Calcium is essential for bone strength and structure, playing a key role in maintaining bone health. Choice B, magnesium, while important for bone health, is found in smaller amounts in bones compared to calcium. Choice C, collagen, is a protein and is a major organic component of bone, not an inorganic material. Choice D, potassium, is an essential mineral for various bodily functions but is not a primary inorganic material found in bones.

4. Where is the scaphoid bone located in the body?

• A. Wrist
• B. Shoulder
• C. Spine
• D. Face

Correct answer: A

Rationale: The correct answer is A: Wrist. The scaphoid bone is one of the carpal bones located in the wrist. It is a small boat-shaped bone that is frequently involved in wrist injuries, such as falls onto an outstretched hand resulting in a scaphoid fracture. Choices B, C, and D are incorrect as the scaphoid bone is not located in the shoulder, spine, or face. Understanding the anatomical location of bones is crucial for diagnosing and treating injuries accurately.

5. When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), what type of reaction occurs?

• A. Combustion
• B. Double displacement
• C. Decomposition
• D. Synthesis

Correct answer: B

Rationale: When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), a double displacement reaction occurs. In this reaction, the positive ions in baking soda switch places with the positive ions in vinegar to form water, carbon dioxide, and a salt. Combustion involves a reaction with oxygen to produce heat and light energy. Decomposition is the breakdown of a compound into simpler substances, which is not the case in the given reaction. Synthesis is the combination of substances to form a more complex compound, which is also not the type of reaction observed when baking soda and vinegar react.

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