Question

The allotrope of this element is the primary absorber of UV solar radiation in Earth's atmosphere. What element is this?
A.Carbon
B.Nitrogen
C.Oxygen
D.Neon
E.Argon

Answer 1

Hint: A layer of ozone is present on the surface of the earth which absorbs UV radiations coming from the sun.
-The constituent of ozone is what we need to know about in order to solve this question.

Complete step by step answer:
The term allotrope means two or more naturally existing forms of the same element, for example diamond and graphite are examples of allotrope of carbon. They have the same constituents, i.e., carbon, but have different structures.
Similarly, ozone is an allotrope of oxygen, it is made of ${O_3}$ and it plays a very crucial role in protection of the earth surface. It acts like a sponge, and absorbs ultraviolet radiation, coming from the sun. Ultraviolet radiations can penetrate inside skins of living organisms, and it can cause skin cancer and other skin diseases if exposed for a longer period of time.
The thickness of the ozone layer is becoming lesser, because of some specific chemicals like chlorofluorocarbons, released by refrigerants, or the $C{O_2}$ released by chemical factories. The depletion of the ozone layer, in turn, results in more exposure of ultraviolet rays in that region. When the ozone layer becomes too thin in a specific area, it is known as an ozone hole.
The ozone layer is also responsible for something called greenhouse effect. In places with lower temperature, where farming is not possible naturally, some glass houses are made, as it traps the warmth from sunlight, which creates an ideal environment for the crops. The ozone layer shows a similar effect on a large scale as it traps the $C{H_4}$ and $C{O_2}$ etc. inside the troposphere layer, and the temperature of earth increases, causing global warming. Global warming is a serious issue, as it causes melting of glaciers which in turn results in flood and loss of resources. There are various ways in which all this could be avoided, as they say, “Plant more trees” and “use public transport” as these small steps could avoid formation of those harmful gases.
Hence, the correct option is C.

Note: The other options given in the question, argon and neon, are called noble gases as these are the most inert of all gases, they are called so because they are the most unreactive species. However there are some exceptions in case of xenon and some other gases.
-The group in the periodic table in which oxygen exists, is also called “chalcogens”