How to name ionic compounds — Reading Comprehension

Formation of an ionic bond, showing electron transfer between atoms to create charged ions.

Ionic compounds are formed from the electrostatic attraction between oppositely charged ions. This process involves the transfer of electrons from a metal atom to a nonmetal atom. The metal atom, having lost one or more electrons, becomes a positively charged ion called a cation. The nonmetal atom, having gained one or more electrons, becomes a negatively charged ion known as an anion. The resulting compound is held together by this strong electrical force.

The systematic naming of ionic compounds follows a straightforward set of rules. The name always begins with the cation, which is the metal ion. This is followed by the name of the anion, which is the nonmetal ion. For a simple anion, the ending of the nonmetal's name is replaced with the suffix "-ide." For example, the compound formed from sodium (a metal cation) and chlorine (a nonmetal anion) is named by combining the cation's name, "sodium," with the modified anion's name, "chloride." Thus, the compound NaCl is called sodium chloride.

Some metals, particularly transition metals, can form cations with different charges. To avoid ambiguity, a Roman numeral is used in parentheses immediately after the metal's name to specify its charge. For instance, iron can form both a +2 ion (Fe2+) and a +3 ion (Fe3+). Therefore, the compound FeCl2​ is named iron(II) chloride, indicating the iron cation has a +2 charge. Similarly, FeCl3​ is named iron(III) chloride, where the iron cation has a +3 charge. This convention ensures that the exact composition of the compound is clear from its name.

The ability to correctly name ionic compounds is a foundational skill in chemistry. It is essential for accurately identifying and communicating about the vast number of compounds that exist, from common table salt to the minerals that form the Earth's crust. This standardized naming system allows scientists and students alike to understand the composition of chemical substances universally.

Fun Fact: The mineral pyrite, often called "fool's gold," is an ionic compound with the chemical formula FeS2​.

What type of particles are formed when atoms gain or lose electrons?

What is a positively charged ion called?

Which part of an ionic compound is named first?

What suffix is added to the root name of a simple nonmetal anion?

How is the charge of a transition metal ion indicated in its name?

Why are Roman numerals used in naming some ionic compounds?

What is the main idea of the reading passage?

If a metal, "X," can form X$^+$ and X$^{2+}$ ions, how would you distinguish between compounds it forms with chlorine?