Properties of covalent compounds

Properties of Covalent Compounds
– Weak intermolecular (between molecules) forces of attraction
– Do not conduct electricity
– Partially soluble in water
– Are made of molecules not ions

There are many types of covalent compounds. We have covered the diatomic molecules such as the oxygen and the nitrogen molecule, however the large majority of covalent compounds are not diatomic and involve several different kinds of atoms. A simple example of this is water. You know this is a commodity we use in everyday life. The formula for water is H2O and the structure of this is shown below:

Notice that for water, there are 2 Hydrogen atoms and 1 oxygen atom as we would expect because oxygen needs 2 electrons to have a complete outer shell and hydrogen needs 1 electron. As a result Oxygen forms two single bonds with Hydrogen.

This may be confusing at first but an easy way to grasp the concept of covalent bonding is to identity how many electrons are needed to complete the outer shell of a non metal atom. If one electron is needed to complete the outershell, then a single bond will be formed with each atom contributing one electron.

If two atoms are in need of 2 electrons then a double bond will be formed with each atom contributing 2 atoms, eg oxygen molecule above.
If one atom needs 2 electrons and the other is in need of only one electron, then 2 single bonds will be formed. For example, the water molecule above.