Question

The two forms of oxygen formed in the atmosphere are:
A. Water and Ozone
B. Ozone and Oxygen
C. Water and Oxygen
D. Water and Carbon dioxide

Answer 1

Hint: Oxygen has two allotropic forms namely, diatomic ($O_2$) and triatomic ($O_3$).

Complete answer: Water ($H_2O$) is formed by the combination of the two atoms of oxygen and one atom of oxygen.
1. Ozone ($O_3$) is made up of three atoms of oxygen that is a triatomic molecule.
Since ozone is made up of one single type of atom that is oxygen so it is one of the forms of oxygen found in the atmosphere.
2. Oxygen ($O_2$) is a diatomic molecule and consists of two atoms of oxygen.
Since oxygen is made up of one single type of atom that is oxygen so it is one of the forms of oxygen found in the atmosphere.
3. Carbon dioxide ($CO_2$) is made up of two different kinds of atoms and is made up of a combination of one atom of carbon and two atoms of oxygen.
So, all the options with the Carbon dioxide ($CO_2$) are eliminated as it is made up of two different kinds of atoms.

Therefore, the option B. is correct.

Note: Earth's atmosphere consists of about 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases.
Trace amounts of carbon dioxide, methane, water vapor, and neon are some of the other gases that form the remaining 0.1 percent.