Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: Dispersion forces are the weakest intermolecular forces present in non-polar covalent compounds due to temporary dipoles. Non-polar compounds have symmetrical distribution of electrons, leading to temporary shifts in electron density causing dispersion forces. Polar compounds (choice A) have permanent dipoles, ionic compounds (choice C) have strong electrostatic forces, and hydrogen compounds (choice D) involve hydrogen bonding - all of which are stronger than dispersion forces and not typically found in non-polar compounds. Therefore, the correct answer is B - non-polar covalent compounds.

Correct Answer: C

Rationale: Group IIIA elements have 3 valence electrons, which they tend to lose to achieve a stable octet electron configuration. By losing 3 electrons, they acquire a +3 charge. This is why the correct answer is C. Choice A is incorrect because Group IIIA elements do not typically gain electrons to have a +1 charge. Choice B is incorrect as they don't lose 2 electrons to have a +2 charge. Choice D is incorrect as they do not gain or lose electrons to have a charge of 0.

Correct Answer: B

Rationale: The correct answer is B: By their chemical properties. The periodic table arranges elements based on their atomic number, which determines their chemical properties. Elements in the same column have similar properties due to their shared electron configurations. This organization helps predict an element's behavior in chemical reactions. Choices A, C, and D are incorrect because atomic mass, physical state, and charge do not determine an element's position in the periodic table or its relationship to other elements.

Correct Answer: C

Rationale: Alpha particles are positively charged and relatively large, so they have low penetrating power. A piece of paper can stop alpha particles because the paper's thickness provides enough material for the particles to collide with and lose their energy through ionization. Aluminum foil and glass are not thick enough to effectively stop alpha particles. Plastic, depending on its thickness, may not provide sufficient shielding to stop alpha particles completely. In summary, the correct answer is C because the thickness of a piece of paper is sufficient to stop alpha particles, while the other choices are not adequate for effective shielding.

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.