HESI A2 Chemistry Questions

Correct Answer: B

Rationale: The correct answer is B: Ionic bonds. Ionic compounds are held together by the attraction between positively and negatively charged ions. This attraction is created when one atom donates electrons to another, forming ions with opposite charges that attract each other. Covalent bonds (A) involve sharing electrons, not transferring them. Hydrogen bonds (C) are weaker interactions between hydrogen atoms and electronegative atoms like oxygen or nitrogen. Metallic bonds (D) involve the delocalized sharing of electrons in a sea of electrons within a metal structure.

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: 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.

Correct Answer: B

Rationale: The correct answer is B: Solid. In solids, particles are tightly packed in a fixed position due to strong intermolecular forces holding them in place. This results in a definite shape and volume. In liquids (choice A), particles are close together but not in fixed positions, allowing them to flow and take the shape of their container. In gases (choice C), particles are far apart and move freely, leading to indefinite shape and volume. In plasma (choice D), particles are highly energized, ionized, and not bound together, making them not tightly packed or in fixed positions.

Correct Answer: B

Rationale: The correct answer is B: Fluorine. Fluorine is the most electronegative element because it has the highest electronegativity value on the periodic table. Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. Fluorine has the highest electronegativity value of 3.98, indicating its strong ability to attract electrons. Oxygen (A) is also highly electronegative but has a lower value than fluorine. Nitrogen (C) is less electronegative than oxygen. Sodium (D) is a metal and has low electronegativity compared to the nonmetals listed.