Which of the following best describes when a covalent bond is considered polar?

• A. When the two atoms involved have different electronegativities, causing an unequal sharing of electrons
• B. When both atoms have identical electronegativities, resulting in equal sharing of electrons
• C. When the bond is formed between two noble gas atoms
• D. When the bond is formed between two metal atoms

Answer: (A)

Verified step by step guidance

1. Understand that a covalent bond involves the sharing of electrons between two atoms.
2. Recall that electronegativity is a measure of an atom's ability to attract shared electrons in a bond.
3. Recognize that if two atoms have identical or very similar electronegativities, the electrons are shared equally, resulting in a nonpolar covalent bond.
4. Identify that when two atoms have different electronegativities, the electrons are shared unequally, causing a partial positive charge on one atom and a partial negative charge on the other; this is a polar covalent bond.
5. Note that bonds between noble gas atoms or metal atoms typically do not form covalent bonds, so these options do not describe polar covalent bonding.