Nursing Elites

1. In the electron cloud model, electrons occupy specific energy levels around the nucleus with varying probabilities. This model depicts electrons existing in distinct energy levels, not fixed orbits, with probabilities of finding them in specific regions.

• A. 2 protons and 6 neutrons
• B. 2 filled s orbitals and 6 filled p orbitals
• C. 2s orbitals with 2 and 6 electrons, respectively
• D. 4 filled electron shells

Correct answer: C

Rationale: The electron cloud model describes electrons existing in distinct energy levels, not fixed orbits. Option C correctly describes the electron configuration of an atom with 2s orbitals containing 2 electrons and 6 electrons in the 2p orbitals. This configuration aligns with the electron cloud model where electrons are found in specific energy levels with varying probabilities. Options A, B, and D do not accurately represent the electron cloud model.

2. What property of a substance refers to its ability to undergo a chemical change and form new substances with different properties?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances with different properties. Density (A), mass (B), and volume (D) are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is mass per unit volume, mass is the amount of matter in a substance, and volume is the space occupied by a substance.

3. Which hormone is produced by the thyroid gland?

• A. Insulin
• B. Thyroxine
• C. Adrenaline
• D. Cortisol

Correct answer: B

Rationale: The correct answer is B: Thyroxine. The thyroid gland produces thyroxine, a hormone essential for regulating metabolism. Insulin is produced by the pancreas to regulate blood sugar levels. Adrenaline is produced by the adrenal glands to prepare the body for the 'fight or flight' response. Cortisol is produced by the adrenal cortex in response to stress, not by the thyroid gland.

4. In the body, muscle tissue is involved in which of the following functions?

• A. Generation of body heat
• B. Joint stabilization
• C. Maintenance of posture
• D. All of the above

Correct answer: D

Rationale: Muscle tissue serves multiple functions in the body, including the generation of body heat, joint stabilization, and maintenance of posture. These functions are essential for movement, stability, and overall bodily functions. The correct answer is 'All of the above' because muscle tissue plays a key role in each of these vital functions. The generation of body heat occurs through muscle activity, joint stabilization is achieved by muscles surrounding joints, and maintaining posture involves muscle contraction to support the body's position. Therefore, all the listed functions are interconnected and rely on the proper functioning of muscle tissue.

5. Which of the following is a property of amphiprotic substances?

• A. React with acids only
• B. React with bases only
• C. Can act as both acids and bases
• D. Are inert in chemical reactions

Correct answer: C

Rationale: The correct answer is C: Can act as both acids and bases. Amphiprotic substances have the ability to donate a proton (act as an acid) or accept a proton (act as a base) depending on the reaction conditions. This dual nature allows them to participate in a wide range of chemical reactions, making them versatile and important in various chemical processes. Choices A and B are incorrect because amphiprotic substances are not limited to reacting with only acids or bases; they can interact with both. Choice D is incorrect because amphiprotic substances are not inert; they actively participate in chemical reactions by donating or accepting protons.

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