Tetravalency of carbon

The idea

With a valency of four, carbon can bond with four carbon atoms or atoms of monovalent elements, and with oxygen, nitrogen, sulphur, chlorine and others; the non-carbon elements give the compound its specific properties.

Four hands

Carbon has a valency of four. Hydrogen has a valency of one.

How many hydrogen atoms can one carbon atom bond with?

• Two
• Four
• Six

Count the bonds

Open every tab. Count the lines around each carbon atom.

Four bonds, many partners

In each picture carbon has four bonds around it. The other atoms it bonds with change, and they decide the specific properties of the compound.

With a valency of four, carbon can bond with four carbon atoms or atoms of monovalent elements, and with oxygen, nitrogen, sulphur, chlorine and others. The non-carbon elements give the compound its specific properties.

Notes

With a valency of four, carbon can bond with four carbon atoms or atoms of monovalent elements, and with oxygen, nitrogen, sulphur, chlorine and others. The non-carbon elements give the compound its specific properties.

Check yourself

How many bonds does each carbon atom make in these compounds?

Answer: 4

Carbon has a valency of four, so it makes four bonds.

In chloroform, CHCl₃, to how many atoms in all is the carbon atom bonded?

Answer: 4

One hydrogen atom plus three chlorine atoms: 1 + 3 = 4 atoms.

What gives a carbon compound its specific properties?

Which statement about the elements carbon forms compounds with is correct?

• The fact that carbon has a valency of four. All the compounds shown have carbon with a valency of four, so that cannot explain their different properties.
• The elements other than carbon present in the molecule — correct. Yes!
• The colour of the carbon atoms. The book says the properties depend on the elements other than carbon present in the molecule.
• Carbon forms compounds only with hydrogen and other carbon atoms. Carbon also forms compounds with oxygen, nitrogen, sulphur, chlorine and many other elements.
• Carbon forms compounds only with oxygen. Carbon forms compounds with hydrogen, nitrogen, sulphur, chlorine and many other elements as well.
• Carbon forms compounds with oxygen, nitrogen, sulphur and chlorine, among others — correct. Yes!