| | | | |

Chemistry

Topic: Carbon

Kingsley IdiagborB.Sc(Hons), NCE, PGDCs, MNSM

Carbon is in group IV and period II in the periodic table. It has atomic number of 6 with electronic configuration of 1s² 2s² 2p^2. The atomic radius and atomic volume are 0.91A^o and 4.58cm³/mol.

The Atomic Structure of Carbon

The electrons per energy level of carbon is 2,4 and the shell model is illustrated in Fig. 1

Physical Properties

Allotropy in Carbon

Carbon exhibits allotropy (or polymorphism) with each allotrope having very different physical properties from the other.

Allotropy:  An element is said to exhibit allotropy when it is found in two or more forms in the same physical state. The different forms are called allotropes. Allotropes differ in physical properties like colour, hardness and even molecular structure. They are, however, usually alike in most chemical properties. An analogous phenomenon of allotropy is polymorphism.

Carbon has three allotropes namely diamond, graphite and the fullerenes. Diamondand graphite are crystalline allotropes while the non-crystalline allotropes are loosely classified as amorphous carbon or fullerenes.

Diamond

Diamond is perhaps the strongest natural substance and this is attributed to the fact that each atom of carbon is linked to four other carbon atoms. This gives diamond a network covalent lattice and it crystallizes in ISOMETRIC SYSTEM.

Properties and uses of Diamond

• Diamond is the strongest natural substance on earth with a density of 3.5g cm^-3
• It is an excellent electrical insulator owing to the structure of diamond - each carbon atom is linked to four others. Since carbon is tetravalent, it means that there is no electron per atom that is free to move about.
• It is transparent and has a high refractive index enabling it to have a high lustre, especially when polished. This is why diamond is used as jewellery.

Graphite

Graphite is made up of hexagonal layers that easily slide over one another. This gives graphite its greasy and lubricant in nature. The layers are formed as a result of the fact that each atom of carbon is connected to three other neighbouring atoms leaving an electron per atom delocalized.

Send in your comments:/Questions

Back | Home | ^ |Next | Close Window |Print now |