Carbon exists in different allotropes including diamond and graphite. Diamond and graphite have very different physical properties despite being made of the same element carbon. This is because the arrangement of carbon atoms differs between the two allotropes, with diamond having the carbon atoms arranged in a tightly bound 3D structure while graphite has the carbon atoms arranged in stacked planar sheets.

2. CARBON
 Carbon belongs to the group IV of
the periodic table.
 It has four electrons in its
outermost orbit, so its valency is
four.
 Carbon is a non-metal.

3. ALLOTROPES OF CARBON
 In nature, pure carbon occur in two forms-
 Diamond
 Graphite

4. WHAT ARE ALLOTROPES ?
 The various physical forms in which element
can exist are called allotropes of that
element.
 Diamond and Graphite – two allotropes of
carbon differ in their physical properties.

5. PHYSICAL PROPERTIES OF
DIAMOND AND GRAPHITE
Property Diamond Graphite
Appearance Transparent Black, Shiny
Hardness Very Hard Soft, slippery to
touch
Thermal Very poor moderate
Conductivity
Electrical Poor Good conductor
Conductivity
Uses Jewellery, drilling Dry cell, electric
arc, lubricant,
pencil lead

6. WHY THE PHYSICAL PROPERTIES OF DIAMOND
AND GRAPHITE ARE SO DIFFERENT?
 Due to the difference in the arrangement of
carbon atoms in diamond and graphite

7. Buckminsterfullerene
Its structure is
much like a football.