Correct the error in each of the following statements: (a) The formula of ammonia is NH3 (b) Molecules of potassium chloride have the formula KCl. (c) Cl-is a cation. (d) CH4 is a polyatomic ion

Verified step by step guidance

1. (a) The formula of ammonia is correct as NH_3. However, if the statement implies an error, it might be due to a typographical mistake or context misunderstanding. Ensure the context is clear that NH_3 is indeed ammonia.
2. (b) Potassium chloride (KCl) is an ionic compound, not a molecule. Molecules are typically covalently bonded, whereas KCl consists of ions.
3. (c) Cl^- is an anion, not a cation. Anions are negatively charged ions, while cations are positively charged.
4. (d) CH_4 is methane, a neutral molecule, not a polyatomic ion. Polyatomic ions are charged species composed of two or more atoms covalently bonded.

Key Concepts

Chemical Formulas

Chemical formulas represent the composition of a substance, indicating the types and numbers of atoms present. For example, NH3 denotes ammonia, which consists of one nitrogen atom and three hydrogen atoms. Understanding how to interpret these formulas is essential for identifying compounds and their properties.

Ionic Compounds

Ionic compounds, such as potassium chloride (KCl), consist of positively charged cations and negatively charged anions. In KCl, potassium (K) is a cation, while chloride (Cl) is an anion. Recognizing the roles of these ions is crucial for understanding the structure and behavior of ionic compounds.

Cations and Anions

Cations are positively charged ions formed when an atom loses electrons, while anions are negatively charged ions formed when an atom gains electrons. For instance, Cl- is an anion, not a cation, as it has gained an electron. This distinction is fundamental in chemistry for predicting the behavior of elements in reactions.