Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The mass number represents the total number of protons and neutrons in an atom's nucleus. The atomic number represents the number of protons. By subtracting the atomic number from the mass number, we are left with the number of neutrons. Therefore, the correct answer is B: Number of neutrons. Summary: A: Number of electrons - Incorrect, as the mass number minus the atomic number does not give the number of electrons. C: Number of protons - Incorrect, as the atomic number itself represents the number of protons. D: Number of isotopes - Incorrect, as isotopes refer to atoms of the same element with different numbers of neutrons, not the result of mass number minus atomic number.

Correct Answer: B

Rationale: The correct answer is B: Alpha. Alpha radiation involves the emission of helium ions, which are essentially helium atoms that have lost two electrons. This type of radiation consists of alpha particles, which are positively charged and relatively heavy. They have low penetration power and can be stopped by a sheet of paper or human skin. Beta radiation (choice A) involves the emission of high-energy electrons or positrons, not helium ions. Gamma radiation (choice C) consists of electromagnetic waves and does not involve the emission of particles. There is no radiation type known as Delta (choice D). Therefore, the correct answer is B as it accurately describes the characteristics of alpha radiation.

Correct Answer: B

Rationale: The correct answer is B: Non-polar. In a covalent bond where electrons are shared equally, the electronegativity of the atoms involved is the same, resulting in a symmetrical distribution of charge. This leads to a non-polar covalent bond. A: Polar bonds occur when there is an unequal sharing of electrons due to differences in electronegativity. C: Ionic bonds involve the complete transfer of electrons from one atom to another, resulting in charged ions. D: Hydrogen bonds are a type of intermolecular force, not a classification of covalent bonds based on electron sharing.

Correct Answer: B

Rationale: The correct answer is B: Nuclear. Nuclear reactions involve changes in the nucleus of an atom, such as nuclear fusion or fission, to achieve stable nuclear configurations by balancing the number of protons and neutrons. Chemical reactions (Choice A) involve changes in electron configurations, not the nucleus. Physical reactions (Choice C) involve changes in state or structure, not nuclear configurations. Mechanical reactions (Choice D) involve forces and motion, not changes in the nucleus for stability. Therefore, option B is the correct choice for reactions taking place in the nucleus to achieve stable nuclear configurations.

Correct Answer: B

Rationale: The correct answer is B: Chemical reaction. In a chemical reaction, bonds are broken and new bonds are formed to create new chemical compounds. The process involves the rearrangement of atoms to form different substances with unique properties. Physical reactions (choice A) involve changes in physical state or appearance without altering the chemical composition. Nuclear reactions (choice C) involve changes in the nucleus of an atom, leading to the formation of different elements. Mechanical reactions (choice D) involve physical forces but do not result in the formation of new chemical compounds.