HESI A2 Chemistry Questions

Correct Answer: B

Rationale: The correct answer is B: Iron. The chemical symbol 'Fe' represents the element iron in the periodic table. Iron is a transition metal with atomic number 26. It is commonly used in construction, manufacturing, and as a vital nutrient in the human body. Lead (choice A), Silver (choice C), and Copper (choice D) have the chemical symbols 'Pb', 'Ag', and 'Cu' respectively, making them incorrect choices. By knowing the periodic table and corresponding chemical symbols, we can easily identify the correct element.

Correct Answer: A

Rationale: The mass number is the sum of protons and neutrons in an atom. Given 6 protons and 6 neutrons, the mass number would be 6+6=12. Electrons do not contribute significantly to the mass number. Therefore, the correct answer is A: 12. Choice B is incorrect as it adds the protons, neutrons, and electrons together. Choice C only considers the number of protons. Choice D is incorrect as it only includes the number of protons.

Correct Answer: C

Rationale: The correct answer is C because an acid reacts with bases to form salt and water through a neutralization reaction. This property is known as the acidic property. Choice A (Bitter taste) is incorrect as acids generally taste sour, not bitter. Choice B (Slippery feel) is incorrect as this describes the texture of bases, not acids. Choice D (Sweet taste) is incorrect as acids typically taste sour, not sweet. In summary, the property of reacting with bases is unique to acids, distinguishing them from other substances.

Correct Answer: A

Rationale: Silicon is a metalloid because it exhibits properties of both metals and non-metals. It is a semiconductor, has a shiny appearance, and conducts electricity to some extent. Lead is a metal, helium is a noble gas, and aluminum is a metal. Therefore, the correct answer is A: Silicon.

Correct Answer: C

Rationale: The correct answer is C: Electrons. Electrons are negatively charged subatomic particles found in the electron cloud surrounding the nucleus of an atom. They are responsible for chemical bonding and electricity conduction. Protons (A) are positively charged, neutrons (B) are neutral, and isotopes (D) are atoms with the same number of protons but different number of neutrons.