Nursing Elites

1. Which number represents the number of protons in an element?

• A. Atomic mass
• B. Mass number
• C. Atomic number
• D. Proton number

Correct answer: C

Rationale: The correct answer is C: Atomic number. The atomic number corresponds to the number of protons in an element. Protons are positively charged subatomic particles found in the nucleus of an atom. Each element has a unique atomic number, which defines its identity based on the number of protons it contains. Choice A, Atomic mass, is incorrect as it refers to the average mass of an atom of an element. Choice B, Mass number, represents the total number of protons and neutrons in an atom's nucleus. Choice D, Proton number, is not a commonly used term in chemistry to indicate the number of protons.

2. What are negatively charged ions called?

• A. Neutrons
• B. Protons
• C. Anions
• D. Cations

Correct answer: C

Rationale: Negatively charged ions are called anions. Anions gain electrons and carry a negative charge, which distinguishes them from cations that are positively charged and neutrons and protons that are subatomic particles found in the nucleus of an atom. Choice A, Neutrons, are neutral subatomic particles found in the nucleus of an atom, not negatively charged ions. Choice B, Protons, are positively charged subatomic particles found in the nucleus of an atom, not negatively charged ions. Choice D, Cations, are positively charged ions that lose electrons, which is opposite to the behavior of negatively charged ions.

3. A radioactive isotope has a half-life of 20 years. How many grams of a 6-gram sample will remain after 40 years?

• A. 8
• B. 6
• C. 3
• D. 1.5

Correct answer: C

Rationale: The half-life of a radioactive isotope is the time it takes for half of the original sample to decay. After each half-life period, half of the initial sample remains. In this case, after the first 20 years, half of the 6-gram sample (3 grams) will remain. After another 20 years (total of 40 years), half of the remaining 3 grams will remain, which is 1.5 grams. Therefore, 3 grams will be left after 40 years. Choice A is incorrect as it doesn't consider the concept of half-life and incorrectly suggests an increase in the sample. Choice B is incorrect as it assumes no decay over time. Choice D is incorrect as it miscalculates the remaining amount after two half-life periods.

4. Which of these types of intermolecular force is the strongest?

• A. Dipole-dipole interaction
• B. London dispersion force
• C. Keesom interaction
• D. Hydrogen bonding

Correct answer: D

Rationale: Hydrogen bonding is the strongest type of intermolecular force among the options provided. It occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and forms a strong electrostatic attraction with an unshared pair of electrons on another electronegative atom. This type of bond is stronger than dipole-dipole interactions, London dispersion forces, and Keesom interactions due to the significant electronegativity difference between the hydrogen and the electronegative atom involved in the bond. The presence of hydrogen bonding contributes to unique properties in substances, such as high boiling and melting points, making it a crucial force in various biological and chemical processes.

5. What are bases or alkaline solutions known as?

• A. Hydrogen acceptors
• B. Solutions of low pH
• C. Hydrogen donors
• D. Amphoteric

Correct answer: A

Rationale: Bases or alkaline solutions are known as 'hydrogen acceptors.' They accept protons (H+) in chemical reactions, as opposed to acids that donate protons. This property allows bases to neutralize acids and form salts. Choice B, 'Solutions of low pH,' is incorrect because bases have high pH values, not low. Choice C, 'Hydrogen donors,' is incorrect as bases do not donate protons but accept them. Choice D, 'Amphoteric,' refers to substances that can act as both acids and bases, which is not the definition of bases. Therefore, the correct answer is A.

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