A compound is a chemical substance that forms when two or more different elements combine in a fixed ratio. Water (H2O), for example, is a compound that is made up of two hydrogen atoms for every one oxygen atom. Sodium chloride (NaCl) is a compound made up of one sodium atom for every chlorine atom.
Hudson, Iowa. Hudson is a city in Black Hawk County, Iowa, United States. The population was 2,282 at the 2010 census. The rural community of Hudson has grown in recent years and is included as a part of the Waterloo-Cedar Falls Metropolitan Statistical Area. Contents.
Hudson is a city in St. Croix County, Wisconsin, United States. As of the 2010 United States Census, its population was 18,937, making it the principal and largest city of the Minneapolis - St. Paul metropolitan area (Wisconsin suburbs). The Hudson area however had a population of 39,713. The village of North Hudson is located directly to the north of Hudson.