Group 16-Physical properties
The Group 16 elements are essential for the existence of life
We need oxygen every minute the day. The next group 16 element, S, is equally important.
It is part of the protein structure of all living organisms.
Here we will look at a few physical properties of the group 16 elements.
Oxygen with weak intermolecular forces of attraction exists as a gas at room temperature.
While the atoms of sulphur are held together by strong covalent bonds and exists in the solid state.
The other group 16 elements Se, Te and Po also exists in the solid state at room temperature.
Moving on, the element oxygen is a non metal and the metallic character increases down the group.
The elements of group 16 mostly exhibit allotropy.
For instance sulphur exists in different forms: Mainly as crystalline and amorphous forms.
Two common crystalline allotropes of sulphur are rhombic and monoclinic.
Let us look at the other physical properties of group 16 elements.
The melting and boiling point of group 16 elements increase down the group.
This is because as we go down the group the size of atom increases.
This increase in size means increase in strength of Van der Waals forces down the group.
Consequently, there is an increase in the melting and boiling points.
The trend can be represented in the graph shown above.
Also, if you notice there is a large difference in melting and boiling points between oxygen and sulphur.
This is due to the difference in atomicity.
The atomicity of sulphur is higher than that of oxygen.
Higher the atomicity, larger will be the energy required to break bonds. And consequently, a higher melting and boiling temperature.
Group 16 elements show interesting physical traits as follows.
Group 16 elements exhibit allotropy.
The trend in the melting point and boiling point of group 16 elements can be represented as above.
The larger difference in melting and boiling point between O and S, is because of higher atomicity of S.