HESI A2 Chemistry Questions

Correct Answer: B

Rationale: The correct answer is B: Group 1 contains the alkali metals. Alkali metals are found in Group 1 because they have a single valence electron, making them highly reactive. They exhibit similar properties due to the presence of this single electron. Group 7 contains the halogens and is known for its high reactivity. Group 2 contains the alkaline earth metals, which have two valence electrons. Group 3 contains the transition metals, which have varying numbers of valence electrons and are less reactive compared to alkali metals. Thus, Group 1 is the only group that fits the characteristics of alkali metals.

Correct Answer: B

Rationale: The correct answer is B: Fluorine. Halogens are a group of elements in the periodic table that include Fluorine, Chlorine, Bromine, Iodine, and Astatine. They are highly reactive nonmetals with seven valence electrons, making them very electronegative. Fluorine specifically is the most reactive and electronegative element, commonly found in compounds like fluoride toothpaste. A: Oxygen is not a halogen. It is a nonmetal but belongs to the chalcogen group in the periodic table. C: Sodium is a metal and belongs to the alkali metal group, not a halogen. D: Carbon is a nonmetal but is not a halogen. It belongs to the p-block elements on the periodic table.

Correct Answer: B

Rationale: The correct answer is B: Neon. Noble gases are a group of elements that are inert and have a full outer electron shell, making them stable and unreactive. Neon belongs to the noble gas group in the periodic table, with a full outer electron shell, making it stable. Oxygen (A) is a reactive nonmetal, hydrogen (C) is a nonmetal but not a noble gas, and argon (D) is also a noble gas but not the correct answer in this case.

Correct Answer: D

Rationale: The correct answer is D: Baking soda. Baking soda, or sodium bicarbonate, has a pH value greater than 7, typically around 8.4 when dissolved in water. This is because it is a basic compound that releases hydroxide ions when dissolved in water, resulting in a pH above 7. In contrast, choices A, B, and C have pH values below 7. Water (choice A) is neutral with a pH of 7, vinegar (choice B) is acidic with a pH below 7, and lemon juice (choice C) is also acidic due to the presence of citric acid. Therefore, baking soda is the only substance among the choices that has a pH value greater than 7.

Correct Answer: D

Rationale: The correct answer is D: Glucose. Glucose is a product of photosynthesis, as plants use sunlight, water, and carbon dioxide to produce glucose (sugar) and oxygen. Glucose is a type of carbohydrate that serves as a primary source of energy for plants and other organisms. Carbon dioxide (A) is one of the reactants needed for photosynthesis, not a product. Oxygen (B) is released as a byproduct of photosynthesis, not a product. Water (C) is also a reactant in photosynthesis, not a product. Therefore, the correct answer is D because glucose is the main product of photosynthesis.