Page 2 - Microsoft Word - P-BLOCK ELEMENTS LN-4

ANOMALOUS PROPERTIES OF CARBON:Reason: exceptionally

small atomic and ionic size,High I.E ,absence of d- orbitals in

valence shell , Highly electronegativev,limit the maximum
covalence to four,ability to form pπ– pπ multiple bonds ,shows

catenation property.

ALLOTROPES OF CARBON

Diamond : In diamond each carbon atom undergoes sp3

hybridisation and linked to four other carbon atoms by using
hybridised orbitals in tetrahedral fashion.

• It is used as an abrasive for sharpening hard tools, in making dyes

and in the manufacture of tungsten filaments for electric light
bulbs.

GRAPHITE: Each carbon atom in hexagonal ring undergoes sp2

hybridization and makes three sigma bonds with three neighbouring
carbon atoms. Fourth electron forms a π bond. The electrons are

delocalised over the whole sheet.

• conducts electricity along the sheet. Graphite cleaves easily

between the layers therefore it is very soft and slippery.

FULLERENES: Buckminsterfullerene contains twenty six- membered
rings and twelve five membered rings. All the carbon atoms are equal

and they undergo sp2 hybridisation.