Nursing Elites

1. If electrons are shared equally in a covalent bond, the bond is classified as what?

• A. Polar
• B. Non-polar
• C. Ionic
• D. Hydrogen

Correct answer: B

Rationale: The correct answer is B: Non-polar. In a non-polar covalent bond, electrons are shared equally between the atoms involved, leading to a balanced distribution of charge and no significant difference in electronegativity between the atoms. This equal sharing results in a non-polar bond. Choices A, C, and D are incorrect because a polar bond involves an unequal sharing of electrons, an ionic bond is formed by the transfer of electrons, and a hydrogen bond is a specific type of non-covalent bond.

2. What is the name of the group of elements that contains chlorine, fluorine, and iodine?

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

Correct answer: B

Rationale: The correct answer is 'Halogens.' Halogens are a group of elements that include chlorine, fluorine, and iodine. These elements are part of Group 17 in the periodic table. They share similar properties such as high reactivity and the ability to readily form compounds. Choice A, 'Alkali metals,' is incorrect as alkali metals are found in Group 1 of the periodic table, which includes elements like lithium and sodium. Choice C, 'Transition metals,' is incorrect as transition metals are located in the middle section of the periodic table, not in Group 17. Choice D, 'Noble gases,' is incorrect as noble gases are in Group 18 and include elements like helium and neon, which are chemically inert.

3. How many neutrons are in an atom of uranium-235?

• A. 92
• B. 125
• C. 143
• D. 235

Correct answer: A

Rationale: The correct answer is A: '92'. To determine the number of neutrons in an atom, you subtract the atomic number (number of protons) from the atomic mass number. For uranium-235, the atomic number is 92, and the atomic mass number is 235. Subtracting 92 from 235 gives us 143 neutrons in an atom of uranium-235. Therefore, options B, C, and D are incorrect as they do not represent the correct number of neutrons in an atom of uranium-235.

4. What is the mass number of an atom with 6 protons, 6 neutrons, and 6 electrons?

• A. 12
• B. 18
• C. 6
• D. 8

Correct answer: A

Rationale: The mass number of an atom is the sum of protons and neutrons. In this case, the atom has 6 protons and 6 neutrons, thus the mass number is 6 + 6 = 12. Therefore, choice A (12) is the correct answer. Choices B (18), C (6), and D (8) are incorrect because the mass number is determined by the sum of protons and neutrons, not the number of electrons or a different combination of particles.

5. What happens in a single displacement reaction?

• A. A compound decomposes into two substances.
• B. An active element displaces a less active element.
• C. A precipitate solid forms from the reaction of two solutions.
• D. The oxidation states of atoms in the reactants change.

Correct answer: B

Rationale: In a single displacement reaction, an active element displaces a less active element in a compound. This process involves one element replacing another in a compound, resulting in the formation of a new compound. Option A is incorrect because a single displacement reaction does not involve the decomposition of a compound into two substances. Option C is incorrect because it describes a precipitation reaction, not a single displacement reaction. Option D is incorrect because it describes oxidation-reduction reactions, not specifically single displacement reactions.

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