Skill 19.6 Demonstrate proficiency at naming compounds and writing formulas

Skill 19.6 Demonstrate proficiency at naming compounds and writing formulas. 

The lUPAC is the International Union of Pure and Applied Chemistry, an 

Naming rules depend on whether the chemical is an ionic compound or a molecular compound containing only covalent bonds. There are special rules for naming acids. The rules below describe a group of traditional semi-systematic names accepted by lUPAC. 

Ionic compounds are named with the cation (positive ion) first. Nearly all cations in inorganic chemistry are monatomic, meaning they just consist of one atom (like Ca , the calcium ion.) This atom will be a metal ion. For common ionic compounds, the alkali metals always have a 1+ charge and the alkali earth metals always have a 2+ charge. 

Many metals may form cations of more than one charge. In this case, a Roman numeral in parenthesis after the name of the element is used to indicate the ion s charge in a particular compound. This Roman numeral method is known as the Stock system. An older nomenclature used the suffix -ous for the lower charge and -ic for the higher charge and is still used occasionally. 

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