Question

What is Allotropy? Name two elements which show allotropy.

Answer 1

Allotropy is the property of the elements to make allotropes in nature. Allotropes are mainly formed by the covalent compounds. Allotropes are different from each other in terms of their structure or crystal lattice. Also they can show different chemical properties too.

Complete answer:
The chemical elements which exist in two or more different forms are known as allotropes of the element. This property of the element is known as allotropy. The elements which show such properties are also known as allotropic elements. The different forms of allotropes must have the same physical state. There must not be a change of state of substance. Generally allotropes are of covalent compounds and which have high catenation power. Catenation power refers to the power of elements to form long chains. These allotropes are different from each other on the basis of physical and chemical properties. The elements which show the property of allotropy are:
$1.$ Carbon
$2.$ Phosphorous
Some examples of allotropes of carbon are:
$1.$ Diamond
$2.$ Graphite
$3.$ Fullerene
Some examples of allotropes of phosphorus are:
$1.$ White Phosphorus
$2.$ Black Phosphorus
$3.$ Red Phosphorous
All these allotropes are different from each other on the basis of their physical properties and chemical properties as diamond is hardest while graphite is not as hard as diamond. The structure of Fullerene is like football in shape. Red Phosphorus is non-poisonous in nature while white phosphorus is poisonous in nature.

Note:
It must be noted that in allotropes there must be the same physical state of all allotropes. Allotropy is sometimes known as allotropism. The atoms in each allotropes are bonded in different manners respectively which makes their crystal structure different from each other. Some are crystalline in nature while some are amorphous in nature.