Nursing Elites

1. The number of protons in an atom is determined by its:

• A. Atomic mass
• B. Electron configuration
• C. Chemical properties
• D. Atomic number

Correct answer: D

Rationale: The number of protons in an atom is determined by its atomic number. The atomic number represents the number of protons in the nucleus of an atom, which also determines the element's identity. Therefore, the correct answer is (D) Atomic number. Choices (A) Atomic mass, (B) Electron configuration, and (C) Chemical properties are not directly related to the number of protons in an atom. Atomic mass is the total mass of protons, neutrons, and electrons in an atom. Electron configuration refers to the arrangement of electrons in an atom's energy levels, and chemical properties are determined by the arrangement of electrons in the outermost energy level.

2. Elements tend to gain or lose electrons to achieve stable electron configurations like those of noble gases. Their group number often indicates the number of electrons gained/lost and the resulting ionic charge, providing a good starting point for prediction.

• A. Ionic bonds involve electron sharing, while metallic bonds involve electron transfer.
• B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
• C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
• D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: C

Rationale: Ionic bonds typically form between metals and non-metals, where one atom donates electrons (cation) and the other accepts electrons (anion). This results in the transfer of electrons. Metallic bonds, on the other hand, occur between metal atoms where electrons are shared among a sea of delocalized electrons, leading to the characteristic properties of metals like malleability and conductivity. Choice A is incorrect because ionic bonds involve electron transfer, not sharing. Choice B is incorrect as ionic bonds are strong, not weak, and are non-directional, while metallic bonds are strong and non-directional. Choice D is incorrect as ionic bonds do not form discrete molecules but rather a lattice structure, whereas metallic bonds form extended structures.

3. What is the condition called when someone experiences a temporary loss of consciousness due to a lack of blood flow to the brain?

• A. Stroke
• B. Epilepsy
• C. Syncope (fainting)
• D. Multiple sclerosis

Correct answer: C

Rationale: Syncope, also known as fainting, is a temporary loss of consciousness caused by a lack of blood flow to the brain. This can occur due to various reasons such as low blood pressure, dehydration, or sudden emotional stress. Strokes involve a disruption of blood flow to the brain resulting in brain cell damage. Epilepsy is a neurological disorder characterized by recurrent seizures. Multiple sclerosis is a chronic autoimmune disease that affects the central nervous system. In this case, the correct answer is 'Syncope' as it directly relates to the temporary loss of consciousness due to decreased blood flow to the brain, distinguishing it from the other options which involve different conditions affecting the nervous system.

4. Which of the following is NOT a characteristic of a chemical reaction?

• A. Formation of new substances
• B. Release or absorption of energy
• C. Change in color
• D. Change in temperature

Correct answer: C

Rationale: A change in color is not always a characteristic of a chemical reaction. While some chemical reactions may result in a change in color, it is not a universal characteristic of all chemical reactions. The formation of new substances, release or absorption of energy, and change in temperature are commonly associated with chemical reactions. Therefore, the correct answer is C, as it does not always occur in every chemical reaction.

5. In a single displacement reaction, one element takes the place of another element in a compound. Which of the following is an example?

• A. 2H2 + O2 -> 2H2O
• B. Zn + 2HCl -> ZnCl2 + H2
• C. CaCO3 -> CaO + CO2
• D. CH4 + 2O2 -> CO2 + 2H2O

Correct answer: B

Rationale: Option B demonstrates a single displacement reaction where zinc (Zn) displaces hydrogen (H) in hydrochloric acid (HCl) to produce zinc chloride (ZnCl2) and hydrogen gas (H2). This reaction exemplifies the concept of one element (Zn) replacing another element (H) in a compound (HCl), which is characteristic of single displacement reactions. Choices A, C, and D do not involve a single element displacing another in a compound, making them incorrect. In choice A, hydrogen and oxygen combine to form water, which is not a single displacement reaction. In choice C, calcium carbonate decomposes into calcium oxide and carbon dioxide, not involving displacement of elements. In choice D, methane reacts with oxygen to form carbon dioxide and water, which is a combustion reaction, not a single displacement reaction.

Similar Questions