Covalent structures (1) questions
Assignment: Question Topic 4.3 : Covalent structures (1)
This page of questions can be marked as direct student access either for assigning as a test or for students to work on in their own time. If you do not wish to use student access, links to downloadable versions of the questions and, separately the worked answers, can be found at Printable versions of written tasks.Draw and upload (either as an image or as a file in pdf format) the Lewis structure for a molecule of each of:
oxygen, nitrogen, tetrachloromethane, carbon dioxide and carbon monoxide.
One Lewis structure for the carbonate ion, CO32–, shows one double C=O bond and two single C-O bonds.
Explain why the bond lengths of all the carbon to oxygen bonds in the carbonate ion are equal.
The oxygen to oxygen bonds in oxygen, O2(g) and ozone, O3(g) are both broken down by ultraviolet light in the atmosphere. Suggest why higher energy ultraviolet light is required to break the oxygen to oxygen bond in oxygen gas compared to the oxygen to oxygen bond in ozone gas.
Suggest a reason why diagrams of organic structures containing a phenyl ring often show the phenyl ring as a hexagon with a circle inside rather than as a hexagon with alternate double and single bonds.
Explain why graphite and diamond both have very high melting points (in the region of 4000 oC) and yet diamond is a poor electrical conductor whereas graphite is a good electrical conductor.
Describe the structures of both diamond and silicon and suggest why silicon has a lower melting point than diamond.
Explain why silicon dioxide has a high melting point (above 1600 ℃) whereas carbon dioxide is a gas at room temperature and pressure.