Question

Oxygen $({{\text{O}}_2})$ and ozone $({{\text{O}}_3})$ are:
A.Allotropes
B.Isotopes
C.Isomers
D.Isobars

Answer 1

Both oxygen and ozone have different formulas but are made up of only one element.

Complete step by step answer:
Let us look at each of the terms in detail:
Isobars: Isobars are those chemical species which are at the same pressure. Since a bar is a unit of pressure and an isobar means the same pressure. But pressure is not mentioned here. So we will neglect this option.
Isomers are those chemical species which have the same molecular formula but different structure or arrangement in space. As we can clearly see that the chemical formula of oxygen and ozone are different. Hence they cannot be isomer as well.
Now coming to isotopes, these are those elements which have the same atomic number but different mass number. But the given species are in molecular state and not in elemental. Hence this option also stands eliminated.
When one chemical element exists in two or more than two different forms, then the different forms in which the element exists are known as allotropes. Oxygen is a single element which exists in two state oxygen and ozone. Hence they both are allotropes. Another example of allotropes is diamond and graphite. They are the allotropes of carbon,

Hence option A is correct.

Note:
Ozone or triatomic oxygen is a very reactive form of oxygen. Ozone gas is present in the stratosphere as an ozone layer. While diatomic oxygen is commonly found in air.