Writing and Naming Ionic and Covalent Compounds

Hi everybody! In today's Chemistry class, we reviewed how to write and name ionic and covalent compounds.

An ionic compound is a compound of a 2 or more particles that are oppositely charged. So for example, a metal ion and a non-metal ion.

If we have a K⁺ and a N^3-
then what is the compound? 


First we look at the charges. K has a positive 1 charge, and N has a negative 3 charge. 
How can we make the charges equal 0? 
+1-3=-2, so what we could do is increase the number of K ions to 3. This would give us a positive 3 charge and a negative 3 charge of N, AND +3-3=0 :) 
So now we know the ionic compound of K⁺ and N^3- is K₃N. 
If we want to name it, it would be Potassium Nitride. Note that the metal is always first.



Now try to write or name these formulas with the Periodic Table:
1) Copper(I) oxide
2) FeO
3) SnCl_{4
There are also ions called complex anions. Anion indicates that it is a negative ion, and complex just means that it is a group of atoms that behave as one atom.}


For example, if we have
Na₂SO₄ Treat SO₄ as basically any other ion. We wouldn't call this sodium sulphur oxide. Instead, there is a specific name for the ion SO₄ and that is sulphate. So this compound is called sodium sulphate.

It gets easier with covalent compounds. Covalent compounds are compounds of a non-metal and another non-metal. They share electrons rather than transferring like ionic compounds.

To name covalent compounds, we use the Greek prefixes:

If we want to name CO₂, we don't say monocarbon dioxide. We never say mono for the first non-metal. If it was N₂O₃, then we would put dinitrogen trioxide, but never monocarbon or mononitrogen.



There are also diatomic molecules. These can be memorized by the acroynm HOFBrINCl. These are a special group of molecules composed of 2 identical atoms.

Here is a video on naming ionic compounds:


And here is the covalent compound:


Here are the answers to the practice questions above:
Cu₂
Iron(II) oxide
Tin(IV) chloride