Nursing Elites

1. Why are elements in Group 18 (Noble gases) generally unreactive?

• A. They have high atomic masses
• B. They lack valence electrons
• C. Their outermost electron shells are completely filled
• D. They exist as single atoms, not molecules

Correct answer: C

Rationale: Elements in Group 18 (Noble gases) are generally unreactive because their outermost electron shells are completely filled. This results in high stability and low reactivity since they have achieved a full valence shell configuration, making them less likely to gain, lose, or share electrons with other atoms. The full valence shell configuration leads to a minimal tendency for these elements to form chemical bonds, hence exhibiting low reactivity. Choices A, B, and D are incorrect because high atomic masses, lack of valence electrons, and existing as single atoms do not directly contribute to the unreactivity of noble gases. It is the full valence shell configuration that is the primary reason for their inert nature.

2. What is the name of a condition where the heart rate is 118 beats per minute (bpm)?

• A. Tachycardia
• B. Apnea
• C. Bradycardia
• D. Tachypnea

Correct answer: A

Rationale: The correct answer is A: Tachycardia. Tachycardia is a condition characterized by a heart rate that exceeds the normal resting rate, typically above 100 bpm. In this case, a heart rate of 118 bpm falls within the range of tachycardia. Apnea (choice B) refers to the temporary cessation of breathing, not related to heart rate. Bradycardia (choice C) is a condition of an abnormally slow heart rate, opposite of the given heart rate. Tachypnea (choice D) is an abnormally rapid breathing rate, not related to heart rate.

3. In the context of optical fibers, chromatic dispersion refers to:

• A. The total internal reflection of light
• B. The spreading of light pulses due to different colors traveling at slightly different speeds
• C. The bending of light at the fiber core-cladding interface
• D. The absorption of light by the fiber material

Correct answer: B

Rationale: Chromatic dispersion in optical fibers refers to the spreading of light pulses due to different colors (wavelengths) traveling at slightly different speeds. This phenomenon can cause the different components of a light pulse to arrive at the receiver at slightly different times, leading to signal distortion. Choice A is incorrect because total internal reflection refers to the phenomenon where light is reflected back into the medium it originated from when hitting the boundary at an angle greater than the critical angle. Choice C is incorrect as it describes the principle of light being guided within an optical fiber through total internal reflection at the core-cladding interface. Choice D is incorrect as the absorption of light by the fiber material does not relate to chromatic dispersion.

4. Which organelle is responsible for storing genetic material?

• A. Mitochondria
• B. Nucleus
• C. Ribosome
• D. Endoplasmic reticulum

Correct answer: B

Rationale: The correct answer is the Nucleus. The nucleus is responsible for storing genetic material (DNA) and controlling cell functions. Mitochondria are known for energy production, not genetic storage. Ribosomes are involved in protein synthesis, not genetic material storage. The endoplasmic reticulum is involved in protein and lipid synthesis, not genetic material storage. Therefore, the nucleus is the organelle primarily responsible for housing the genetic material within a cell.

5. In a neutral atom, the number of electrons is:

• A. Must be equal to the number of protons.
• B. Must be less than the number of protons.
• C. Must be greater than the number of neutrons.
• D. Can vary depending on the atom's temperature.

Correct answer: A

Rationale: In a neutral atom, the number of electrons must be equal to the number of protons to maintain electrical neutrality. Electrons carry a negative charge while protons carry a positive charge. By having an equal number of electrons and protons, the positive and negative charges balance each other out, resulting in an electrically neutral atom. Choice B is incorrect because in a neutral atom, the number of electrons and protons must be equal. Choice C is incorrect as it compares electrons to neutrons, which are not directly related in determining an atom's charge. Choice D is incorrect as the number of electrons in a neutral atom is not dependent on the atom's temperature but rather on the atom's balance of positive and negative charges.

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