Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The correct answer is B: +2. Group IIA elements have a valence of +2 because they have 2 valence electrons in their outer shell. These elements lose these 2 electrons to achieve a stable octet configuration, resulting in a +2 charge. Choice A is incorrect because Group IIA elements do not have a charge of 1. Choice C is incorrect because Group IIA elements do not typically have a negative charge of -3. Choice D is incorrect because Group IIA elements do not have a charge of 0; they lose 2 electrons to become positively charged.

Correct Answer: A

Rationale: The correct answer is A: 1. In a single bond, only one pair of electrons is shared between two atoms, resulting in a stable bond. This shared pair of electrons creates a strong attraction between the atoms, holding them together. The other choices (B, C, D) are incorrect as they represent the number of pairs of electrons shared in double, triple, or quadruple bonds, respectively, which involve 2, 3, or 4 pairs of electrons being shared, not in a single bond. Thus, the correct answer is A because a single bond involves only one pair of shared electrons.

Correct Answer: A

Rationale: The Group IA elements, also known as alkali metals, have a +1 charge. This is because they have one valence electron, which they readily lose to achieve a stable electron configuration. This results in them forming ions with a +1 charge. Therefore, the correct answer is A. Choice B (+2) is incorrect because alkali metals do not typically form ions with a +2 charge due to their tendency to lose only one electron. Choice C (+3) is also incorrect as alkali metals do not form ions with a +3 charge. Choice D (0) is incorrect because alkali metals are known for their tendency to lose electrons to achieve a stable configuration, resulting in a positive charge.

Correct Answer: C

Rationale: The correct answer is C: Combustion. Combustion is a chemical reaction where a compound reacts with oxygen to produce heat, light, and often carbon dioxide and water. In this type of reaction, oxygen is a reactant and typically a hydrocarbon or organic compound is the fuel. Decomposition involves a compound breaking down into simpler substances, synthesis is when two or more substances combine to form a more complex compound, and single replacement is when one element replaces another in a compound. Combustion specifically involves the reaction with oxygen, making it the correct choice in this scenario.

Correct Answer: C

Rationale: The correct answer is C: Cations. Positively charged ions are called cations because they have lost electrons, resulting in a net positive charge. Neutrons (A) are neutral particles found in the nucleus, not charged. Protons (B) are positively charged particles in the nucleus but not considered ions. Electrons (D) are negatively charged particles orbiting the nucleus and form anions when gained. Therefore, Cations are the correct answer as they specifically refer to positively charged ions due to electron loss.