An anion is characterized by what type of charge?

An anion is characterized by a negatively charged state. In the context of chemistry, an anion is formed when an atom or molecule gains one or more electrons. This increase in electrons results in a higher number of negatively charged particles compared to positively charged protons in the atom, hence giving the anion its negative charge.

Understanding anions is important in wastewater treatment because they often play significant roles in various chemical reactions and processes, such as the formation of precipitates and the behavior of contaminants. Anions can include common ions like chloride (Cl^-), sulfate (SO4^2-), and nitrate (NO3^-), all of which are essential to consider when monitoring and treating wastewater.

The other potential answers do not appropriately describe the nature of anions. Neutral particles have an equal number of protons and electrons, thus carrying no charge. Positively charged ions are known as cations, which are distinct from anions, while the idea that the charge of an anion varies is incorrect, as anions are specifically defined by their negative charge in all instances.