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8. Chemical Reactivity eLearn.Punjab

8.2.3 Significance of Non-metals

Although non-metals are fewer than metals, yet they are highly significant. They are equally
important for human beings, animals and plants. In fact, life would not have been possible without
the presence of non-metals on earth.
i- Major components of earth’s crust, oceans and
atmosphere (as shown in table 1.1) are non-
metals: oxygen has the highest percentage in
earth’s crust (47%) and oceans (86%) and it is
second (21%) to nitrogen in atmosphere. It
indicates the importance of oxygen in nature. To
maintain the balance for the amount of non-metals in nature, different cycles like water cycle,
nitrogen cycle, etc have been established naturally.
ii- Non-metals are essential part of the body structure of all living things. Human body is made
up of about 28 elements. But about 96% of the mass of the human body is made up of just 4
elements i.e. oxygen 65%, carbon 18%, hydrogen 10% and nitrogen 3%. Similarly, plant bodies
are made up of cellulose, which is composed of carbon, hydrogen and oxygen.
iii- Life owes to non-metals as without O2 and CO2 (essential gases for respiration of animals and
plants, respectively), life would not have been possible. In fact, these gases are essential for the

existence of life.
iv- All eatables like carbohydrates, proteins, fats, vitamins, water, milk etc which are necessary
for the growth and development of body that are made up of non-metals; carbon, hydrogen
and oxygen. It shows non- metals play a vital role for the maintenance of life.
v- The essential compound for the survival of life of both animals and plants is water, which is
made up of non-metals. Water is not only the major part by mass of animals and plants
bodies, but it is also essential to maintain the life. We can survive without water for days but
not for a long period; its shortage may cause death.
vi- Another important non-metal is nitrogen, which is 78% in atmosphere and is necessary for the

safety of life on earth. It controls the fire and combustion processes, otherwise all the things
around us could burn with a single flame.
vii- Non-metals are playing essential role for the communication in life. All fossil fuels which are
major source of energy; coal, petroleum and gas are made up of carbon and hydrogen. Even
the essential component of combustion of fossil fuels, oxygen is also a non-metal.

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