Nursing Elites

1. What property of a substance remains constant regardless of the amount of the substance present?

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

Correct answer: c

Rationale: Density remains constant for a specific substance regardless of the quantity present. It's the mass per unit volume and remains the same for a substance.

2. Which statement accurately describes the electron cloud model of the atom?

• A. Electrons precisely orbit the nucleus in defined paths.
• B. Electrons occupy specific energy levels around the nucleus with varying probabilities.
• C. Electrons are clustered tightly within the nucleus.
• D. Electrons move randomly throughout the entire atom.

Correct answer: B

Rationale: Electrons occupy specific energy levels around the nucleus with varying probabilities. The electron cloud model depicts electrons existing in distinct energy levels, not fixed orbits, with probabilities of finding them in specific regions.

3. What is the Aufbau principle?

• A. The principle that electrons fill orbitals in order of increasing energy.
• B. The principle that electrons cannot be in the same orbital with the same spin.
• C. The principle that the maximum number of electrons in an orbital is 2n^2, where n is the energy level of the orbital.
• D. The principle that the attractive force between an electron and the nucleus is inversely proportional to the distance between them.

Correct answer: A

Rationale: The Aufbau principle is a fundamental concept in atomic structure that determines the order in which electrons fill the available orbitals in an atom. It states that electrons occupy orbitals in order of increasing energy levels, starting with the lowest energy level and progressing to higher energy levels. This principle is based on the fact that electrons in lower energy levels are more stable and have a lower energy state than electrons in higher energy levels.

4. Identify the comprehensive protection for the brain.

• A. Skull
• B. Meninges (Membranes)
• C. Cerebrospinal fluid
• D. All of the above

Correct answer: D

Rationale: Rationale: A) The skull provides a hard, protective covering for the brain, shielding it from external trauma and injury. B) The meninges are three layers of membranes (dura mater, arachnoid mater, and pia mater) that surround the brain and spinal cord, providing additional protection and cushioning. C) Cerebrospinal fluid is a clear, colorless fluid that surrounds the brain and spinal cord, acting as a shock absorber and providing nutrients to the central nervous system. Together, the skull, meninges, and cerebrospinal fluid work in conjunction to provide comprehensive protection for the brain, making option D the correct answer.

5. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:

• A. Glucose
• B. Sodium and potassium ions
• C. Neurotransmitters
• D. Myelin

Correct answer: B

Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.

6. What is the term for the process of breaking a large molecule into smaller fragments by applying heat?

• A. Polymerization
• B. Hydrogenation
• C. Isomerization
• D. Pyrolysis

Correct answer: D

Rationale: Pyrolysis is the process of breaking down large molecules into smaller fragments by applying heat. The other choices involve different chemical processes.

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