Naming Ionic Compounds

An ionic compound is composed of a positive ion called a cation bonded to a negative ion called an anion. The cation can either be a metal or the ammonium ion, while the anion is a non-metal. 

Generally, ionic bonds form to lower the potential energy between positive and negative ions. 

How does an Ionic Bond form? 

The number of electrons in the outer shell of an element is based on its group number. The sodium (Na) atom is in Group 1 and the chlorine (Cl) atom is in Group 7. 

Electron Arrangements

Metals transfer their electron(s) to nonmetals based on differences in polarity and electronegativity properties. 

Oxidation-Reduction-Transfer-Electrons-Lose-GainTransfering Electron(s)The transferring of electrons creates ions with opposite charges that are attracted to each other. 

Sodium-Chloride-Solid-Ions-Binary-CompoundStructural Formula of Sodium Chloride (NaCl)

Lattice energy represents the energy released when 1 mole of an ionic crystal is formed from its gaseous ions. The stronger the lattice energy of an ionic compound then the greater the strength of the ionic bond, the higher its boiling point and melting point. 

Naming Ionic Compounds with Main Group Metals 

The Main Group Metals exclude the transition metal elements. 

Periodic-Table-Main-Group-Transition-MetallicPeriodic Table (Main Group & Transition Metals)

When it comes to naming an ionic compound with a main group metal we can use a set of easy to follow rules. 

STEP 1: The metal is named and written first. 

For example, if we are given BaCl2 the name begins with barium

STEP 2: The nonmetal keeps its base name but has its suffix ending changed to –ide. 

Base-Names-Non-MetalsBase Names of Non-MetalsFor BaCl2 the nonmetal is chlorine and after its ending is changed we have chloride

STEP 3: Combine the first and last name to get the overall name of the ionic compound. 

The name of BaCl2 is barium chloride.

Naming Ionic Compounds with Transition Metals 

The Transition Metals and Inner Transition Metals, of which are further divided into Lanthanides and Actinides are sometimes referred to as the Group B Elements.  

Periodic-Table-Transition-MetalsPeriodic Table (Transition Metals)

The transition metals have varying oxidation numbers and therefore possess multiple charges. As a result of these different potential charges we must use Roman Numerals when naming ionic compounds with transition metals. 

STEP 1: Determine the positive charge of the transition metal. 

For example, if we are given MnBr5 we will determine the charge of manganese by using the charge of bromine and the overall compound. 

Transition-Metal-ChargeCalculating Transition Metal Ion Charge

For MnBr5 we begin the name with manganese (V)

STEP 2: The nonmetal keeps its base name but has its suffix ending changed to –ide.

Base-Name-Non-Metals-Nomenclature-IUPACBase Name of Non-Metals For MnBr5 the nonmetal is bromine and after its suffix ending is changed we have bromide

STEP 3: Combine the first and last name to get the overall name of the ionic compound. 

The name of MnBr5 is manganese (V) bromide.

Naming Ionic Compounds with Polyatomic Ions 

Recall that polyatomic ions represent compounds composed of multiple elements that possess an overall charge. 

When it comes to naming an ionic compound with a polyatomic ion(s) then we do the following: 

STEP 1: The positive ion named and written first. If the positive ion is a transition metal with multiple charges then we use a roman numeral. If the positive ion is a polyatomic ion then it keeps its name. 

For example, if we are given NH4NO2 the name begins with ammonium

STEP 2: The negative ion is written and named secondly. 

In NH4NO2 the negative ion is nitrite.

STEP 3: Combine the first and last name to get the overall name of the ionic compound. 

The name of NH4NO2 is ammonium nitrite.

How to determine the Ionic Compound Formula 

If we want to write the formula of an ionic compound from the name then we must work with the charges of the elements. 

Elements-Charges-Cheat-Sheet-Alkali-Alkaline-Earth-Halogen-Charges of Elements List

STEP 1: Based on the name of the ionic compound give the two ions that are involved. . 

For example, if we are given the name of aluminum oxide. 

Element-ChargesElement Charges

Alumium is in Group 3 and has a +3 charge and oxygen is in Group 6 and has a -2 charge. 

STEP 2: When the charges of the two ions are different numbers then we crisscross them. 

Aluminum-oxide-Al2O3Writing Formulas (Aluminum oxide)

When the charges of the two ions are the same number then they simply cancel out. 

Writing Formulas (Calcium oxide)

Other Models of Chemical Bonding

Besides naming ionic compounds it’ll become important to know how to name covalent compounds/molecular compounds and acids. Unlike ionic compounds, covalent compounds have the sharing of electrons between non-metals.