Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The correct answer is B: Double replacement. In this type of reaction, two ionic compounds swap ions to form two new compounds. The cations and anions switch partners, leading to the formation of two different ionic compounds. This process is also known as metathesis. Single replacement (A) involves an element replacing another in a compound. Synthesis (C) involves the combination of two or more substances to form a single compound. Decomposition (D) involves a single compound breaking down into simpler substances. Double replacement is the only option where two ionic compounds exchange partners, making it the correct choice in this scenario.

Correct Answer: D

Rationale: Dispersion forces are the weakest intermolecular force because they are caused by temporary fluctuations in electron distribution, leading to temporary dipoles. These forces exist between all molecules, regardless of polarity. Dipole interactions are stronger as they involve permanent dipoles in polar molecules. Hydrogen bonding is even stronger, occurring between a hydrogen atom bonded to a highly electronegative atom and another electronegative atom. Van der Waals forces encompass both dipole interactions and dispersion forces. Thus, dispersion forces are the weakest intermolecular force among the given options.

Correct Answer: B

Rationale: The correct answer is B: Non-polar. In a covalent bond where electrons are shared equally, the electronegativity of the atoms involved is the same, resulting in a symmetrical distribution of charge. This leads to a non-polar covalent bond. A: Polar bonds occur when there is an unequal sharing of electrons due to differences in electronegativity. C: Ionic bonds involve the complete transfer of electrons from one atom to another, resulting in charged ions. D: Hydrogen bonds are a type of intermolecular force, not a classification of covalent bonds based on electron sharing.

Correct Answer: B

Rationale: The correct answer is B (-2). Group VIA elements, also known as Chalcogens, have 6 valence electrons. They typically gain 2 electrons to achieve a stable octet configuration, resulting in a -2 charge. Option A (-1) is incorrect because gaining 1 electron would not complete the octet. Option C (-3) is incorrect because gaining 3 electrons is energetically unfavorable. Option D (0) is incorrect because Group VIA elements tend to gain electrons to achieve stability.

Correct Answer: C

Rationale: The correct answer is C, atomic number. The atomic number represents the number of protons in an element. This is because the atomic number is the unique identifier of an element and determines its chemical properties. Protons are the positively charged particles in the nucleus of an atom, and the number of protons defines the element's identity. Explanation for incorrect choices: A: Atomic mass represents the average mass of all isotopes of an element, not the number of protons. B: Mass number is the sum of protons and neutrons in an atom, not just the number of protons. D: "Proton number" is not a standard term in chemistry, and it does not specifically refer to the number of protons in an element.