Chemistry HESI A2 Quizlet

Correct Answer: C

Rationale: The correct answer is C: Covalent bonds are the strongest type of chemical bond. In covalent bonds, atoms share electrons, creating a strong bond between them. This sharing of electrons results in a stable molecular structure. Ionic bonds (choice A) are strong but not as strong as covalent bonds because they involve the transfer of electrons, leading to weaker attractions. Hydrogen bonds (choice B) are weaker than covalent bonds as they are formed between hydrogen atoms and highly electronegative atoms like oxygen or nitrogen. Metallic bonds (choice D) are not as strong as covalent bonds because they involve the sharing of electrons among a sea of delocalized electrons in metals, leading to a weaker bond compared to covalent bonds.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C (Aluminum foil) is correct: 1. Beta radiation particles are high-energy electrons or positrons. 2. Aluminum foil has a high atomic number and density, making it effective at stopping beta particles. 3. The electrons in the aluminum atoms interact with the beta particles, causing them to lose energy and stop. 4. Being thin and dense, aluminum foil can effectively block beta radiation particles. Summary of why other choices are incorrect: A. Plastic: Plastic is not dense enough to effectively stop beta particles. B. Glass: While glass is denser than plastic, it is not as effective as aluminum foil in stopping beta radiation. D. Concrete: Concrete is dense, but it is not as effective as aluminum foil in stopping beta particles due to its composition and thickness.

Correct Answer: A

Rationale: The correct answer is A: Unequal sharing of electrons. In a covalent bond, when two different atoms with different electronegativities come together, one atom attracts the shared electrons more strongly than the other, leading to an uneven distribution of electron density. This results in a dipole moment where one end of the bond is slightly positive and the other slightly negative. Choices B, C, and D are incorrect because in covalent bonds, electrons are not fully transferred or exchanged, but rather shared between atoms, leading to the creation of a dipole due to the unequal sharing of electrons.

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: B

Rationale: The correct answer is B (2). In a double covalent bond, two electron pairs are shared between two atoms. This is achieved by the sharing of two pairs of electrons, resulting in a total of four electrons being shared. However, since each pair consists of two electrons, the number of electron pairs shared to form a double covalent bond is 2. Choices A, C, and D are incorrect because a double bond involves the sharing of 2 electron pairs, not 1, 3, or 4 pairs.