Nursing Elites

1. What is the primary difference between ionic and metallic bonding?

• A. Ionic bonds involve electron transfer, while metallic bonds involve electron sharing.
• 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: B

Rationale: Ionic bonds involve electron transfer, where one atom completely donates an electron to another, resulting in discrete molecules. On the other hand, metallic bonds are non-directional and strong, formed by a 'sea' of delocalized electrons shared among all metal atoms. This shared electron cloud allows for strong bonding throughout the entire material, making metallic bonds non-directional and strong compared to the directional and weaker nature of ionic bonds. Choice A is incorrect because metallic bonds do not involve electron sharing but rather the sharing of a sea of delocalized electrons. Choice C is incorrect as metallic bonds can also exist between metal atoms, not just between metals and non-metals. Choice D is incorrect because metallic bonds do not form discrete molecules but rather extended structures due to the sharing of electrons among all metal atoms.

2. What is the waxy or oily substance produced by sebaceous glands that helps lubricate the skin and hair?

• A. Keratin
• B. Melanin
• C. Sebum
• D. Sweat

Correct answer: C

Rationale: Sebum is the waxy or oily substance produced by sebaceous glands. It helps lubricate the skin and hair, keeping them moisturized and protected. Keratin is a protein that makes up hair, skin, and nails, providing structure and strength. Melanin is a pigment that gives color to the skin, hair, and eyes, providing protection against UV radiation. Sweat is a watery fluid produced by sweat glands to help regulate body temperature by cooling the body through evaporation.

3. Which group of elements is known for their vibrant colors and is commonly used in fireworks?

• A. Noble gases
• B. Alkali metals
• C. Halogens
• D. Transition metals

Correct answer: D

Rationale: The correct answer is D: Transition metals. Transition metals are known for their vibrant colors and are commonly used in fireworks due to their ability to emit specific colors of light. The diverse electronic configurations of transition metals allow them to produce a variety of hues, making them ideal for creating colorful displays in fireworks. Choice A, Noble gases, do not typically produce vibrant colors in fireworks as they are colorless and odorless gases. Choice B, Alkali metals, are not known for their colorful displays in fireworks. Choice C, Halogens, can produce colors in fireworks, but they are not as commonly used for their vibrant hues compared to transition metals.

4. According to the periodic table, which of the following elements is the least reactive?

• A. Fluorine
• B. Silicon
• C. Neon
• D. Gallium

Correct answer: C

Rationale: Neon is the least reactive among the given elements because it belongs to the noble gases group in the periodic table. Noble gases have a full valence shell of electrons, making them highly stable and least likely to react with other elements. Fluorine is the most reactive non-metal due to its high electronegativity. Silicon is a metalloid with moderate reactivity, falling between metals and nonmetals. Gallium is a metal with higher reactivity compared to Neon, but it is not as reactive as Fluorine.

5. What effect does a catalyst have on a chemical reaction?

• A. It speeds up the reaction.
• B. It slows down the reaction.
• C. It makes a reaction go in reverse.
• D. It prevents a reaction from taking place.

Correct answer: A

Rationale: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It works by providing an alternate pathway for the reaction to occur, lowering the activation energy needed for the reaction to proceed. As a result, more reactant molecules can overcome this energy barrier and participate in the reaction, leading to a faster overall reaction rate. This explanation contradicts choices B, C, and D as a catalyst does not slow down, reverse, or prevent a reaction; instead, it accelerates the reaction by facilitating a more efficient route for the reaction to take place. Therefore, the correct answer is that a catalyst speeds up the reaction.

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