Chemistry HESI A2 Quizlet

Correct Answer: A

Rationale: The correct answer is A because a balanced chemical equation must satisfy the law of conservation of mass. This means that the number of atoms of each element must be the same on both the reactant and product sides. This ensures that no atoms are gained or lost during a chemical reaction. Explanation for why the other choices are incorrect: B: An equation with more products than reactants does not follow the law of conservation of mass. C: Balancing the number of molecules is important, but the key factor is balancing the number of atoms of each element. D: Equal masses on both sides do not necessarily guarantee that the number of atoms of each element is the same.

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: C

Rationale: The correct answer is C: Ionic. In an ionic bond, electrons are transferred from one atom to another, resulting in the formation of positively and negatively charged ions that are attracted to each other due to electrostatic forces. This bond is formed between a metal and a non-metal. Covalent bonds (choice A) involve the sharing of electrons between atoms, not the transfer. Metallic bonds (choice B) occur between metal atoms sharing a sea of electrons. Hydrogen bonds (choice D) are weak attractions between a hydrogen atom and a highly electronegative atom.

Correct Answer: C

Rationale: The correct answer is C: Anions. Negatively charged ions are referred to as anions because they have gained extra electrons, resulting in a negative charge. Neutrons (A) are neutral particles found in the nucleus of an atom. Protons (B) are positively charged particles found in the nucleus. Cations (D) are positively charged ions that have lost electrons. Therefore, based on the definition of negatively charged ions, anions are the correct choice.

Correct Answer: B

Rationale: The sum of protons and neutrons in an element represents the mass number. Protons and neutrons are located in the nucleus and contribute to the mass of an atom. The atomic number (A) is the number of protons in an atom, not the sum of protons and neutrons. Atomic mass (C) is the average mass of an element's isotopes, considering their abundance, and is not the sum of protons and neutrons. Neutron number (D) refers to the specific number of neutrons in an atom, not the total mass of the nucleus. Therefore, the correct answer is B, as it accurately represents the total mass of an atom.