Ionic Compound

Ionic Compound

An ionic compound is a compound formed by ions bonding together through electrostatic forces. For example Table salt, Nacl, is an ionic compound. Cations and anions are used to help to name a chemical formula. Cation is a positively charged ion, with fewer electrons than protons and anion is a negatively charged ion, with more electrons than protons.

The Sabalic Cross Method is used to find the general formula for ionic compounds.

For monatomic ions, you simply take the absolute value of the ionic charge for the positively charge ion and make it the subscript for the negatively charged ion and vice versa.

For example Al +3 and Cl -1 the 3 becomes the subscript for the chloride ion and the 1 becomes understood for aluminum, to form aluminum chloride AlCl3.

Ionic compounds are Metals plus nonmetals. To name a compound that contains two elements, identify the cation and anion. Name the cation first followed by the name of the anion. An ionic formula consists of positively and negatively charged ions. Total positive charge must be equal to total negative charge. The symbol of the metal is written first followed by the symbol of the nonmetal.

Ionic compounds that form from polyatomic ions can also make use of the Sabalic cross method. The only additional step is to include parenthesis around the polyatomic ion if it has a subscript other than one. For example Mg+2 and OH-1 the 2 becomes the subscript for the hydroxide ion, but a set of parenthesis is needed to indicate 2 of each the O and the H. The 1 becomes the understood subscript for Mg. Magnesium Hydroxide Mg(OH)2.

A metal element plus a nonmetal element forms an ionic compound. To name an ionic compound, you have to name the metals and nonmetals second. For some of them you use the suffix-ide; and for some of them you use Roman numeral in ( ) after the name of the cation.