Question

Based on the electronegativities K = 0.8, H = 2.1, Br = 2.8, which of the following statements is true? a) H2, Br2, and HBr are nonpolar covalent molecules. b) KBr is a nonpolar covalent compound and HBr is an ionic compound. c) HBr is a nonpolar covalent compound and Br2 is a polar covalent molecule. d) H2 is a nonpolar covalent molecule and HBr is a polar covalent molecule.

Answer 1

The correct statement is that H2 is a nonpolar covalent molecule and HBr is a polar covalent molecule, based on the electronegativity values of the atoms involved.

Step-by-step explanation:

Based on electronegativities, the correct statement is: d) H2 is a nonpolar covalent molecule and HBr is a polar covalent molecule. Electronegativity differences determine the type of bond formed between atoms. A large difference typically indicates an ionic bond, while smaller differences indicate covalent bonds. For molecules like H2, where the atoms involved have identical electronegativities, the bond is nonpolar covalent because the electrons are shared equally. In contrast, HBr has atoms with different electronegativities (H = 2.1, Br = 2.8), leading to unequal sharing of electrons and a polar covalent bond.

KBr, with K having an electronegativity of 0.8 and Br's 2.8, has a difference great enough that it's typically considered ionic, not nonpolar covalent as one of the incorrect statements suggests.

Answer 2

The correct answer is: d) H2 is a nonpolar covalent molecule and HBr is a polar covalent molecule.

Electronegativity is a measure of an element's ability to attract electrons in a chemical bond. In the given options, H has an electronegativity of 2.1, which is significantly higher than K (0.8) and Br (2.8).

In H2, both hydrogen atoms have similar electronegativities, so they share electrons equally, resulting in a nonpolar covalent bond. In HBr, the electronegativity difference between H and Br is significant, causing Br to pull electrons closer to itself, creating a polar covalent bond with partial charges.

The other options are not correct because they do not correctly describe the polarity of the mentioned molecules and compounds based on electronegativity differences.