Nursing Elites

1. Which of the following elements is a halogen?

• A. Oxygen
• B. Fluorine
• C. Sodium
• D. Carbon

Correct answer: B

Rationale: The correct answer is 'Fluorine' (Choice B) as it is a halogen. Halogens are a group of elements that include fluorine, chlorine, bromine, iodine, and astatine. They are highly reactive nonmetals located in Group 17 of the periodic table. Oxygen (Choice A) is a nonmetal but not a halogen. Sodium (Choice C) is a metal, and Carbon (Choice D) is a nonmetal, neither of which belong to the halogen group.

2. What is the correct electron configuration for magnesium?

• A. 1s² 2s²
• B. 1s² 2s² 2p⁶
• C. 1s² 2s² 2p⁶ 3s²
• D. 1s² 2s² 2p⁶ 3s² 3p¹

Correct answer: C

Rationale: The electron configuration of an element is determined by following the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level. Magnesium has an atomic number of 12, meaning it has 12 electrons. The electron configuration of magnesium fills the 1s, 2s, 2p, and 3s orbitals to accommodate all 12 electrons. Therefore, the correct electron configuration for magnesium is 1s² 2s² 2p⁶ 3s². Choice A is incorrect as it only includes 4 electrons and stops at the 2s orbital. Choice B is incorrect as it includes 8 electrons and stops at the 2p orbital. Choice D is incorrect as it includes 13 electrons and extends to the 3p orbital, which is beyond the actual electron configuration of magnesium.

3. Which compound contains a polar covalent bond?

• A. O
• B. F
• C. Br
• D. H₂O

Correct answer: D

Rationale: The compound 'H₂O' (water) contains a polar covalent bond. In a water molecule, the oxygen atom is more electronegative than the hydrogen atoms. As a result, the electrons in the O-H bonds are unevenly shared, leading to a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. This unequal sharing of electrons creates a polar covalent bond in water. Choices A, B, and C are incorrect because they represent individual elements, not compounds, and do not involve the concept of polar covalent bonds.

4. What is atomic mass?

• A. Number of protons in an atom
• B. Sum of protons and neutrons
• C. Number of neutrons in an atom
• D. Average weight of an element

Correct answer: B

Rationale: Atomic mass, also known as atomic weight, is the sum of the number of protons and neutrons in an atom. It represents the average mass of an atom of an element, taking into account the different isotopes and their relative abundance. Neutrons contribute to the atomic mass alongside protons, while the number of neutrons alone is not the definition of atomic mass. Choice A is incorrect because it refers only to the number of protons, not the complete atomic mass. Choice C is incorrect as it focuses solely on the number of neutrons, excluding the contribution of protons. Choice D is incorrect as it mentions the 'average weight of an element,' which is related to atomic mass but does not encapsulate the specific definition of atomic mass as the sum of protons and neutrons.

5. Which of these intermolecular forces might represent attraction between atoms of a noble gas?

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

Correct answer: B

Rationale: Noble gases are non-polar molecules without a permanent dipole moment. The only intermolecular force applicable to noble gases is the London dispersion force, also known as Van der Waals forces. This force is a temporary attractive force resulting from the formation of temporary dipoles in non-polar molecules. Dipole-dipole interactions, Keesom interactions, and hydrogen bonding involve significant dipoles or hydrogen atoms bonded to electronegative atoms, which do not apply to noble gases.

Similar Questions