Final answer:
The polyatomic ion with a +1 charge is the ammonium ion (NH4+), which is formed when a hydrogen ion bonds with an ammonia molecule.
Step-by-step explanation:
The student asked which polyatomic ion has a +1 charge. Polyatomic ions are clusters of atoms covalently bonded together that carry an overall electrical charge. The correct answer is option (C), the ammonium ion (NH4+). The ammonium ion is created when a hydrogen ion (H+) attaches to an ammonia (NH3) molecule via a coordinate covalent bond, resulting in a positively charged ion. Unlike anions that usually end with the suffix -ide (like CN- or OH-), the name of polyatomic cations typically ends with -ium, as seen with the ammonium ion. Therefore, the correct answer to the student's question about the polyatomic ion with a +1 charge is (C) NH4+, the ammonium ion.