The Second Step On The Path
To Matter: Molecules
What is it that makes the objects you see in
your surroundings different from each other? What is it that discriminates
their colours, shapes, smells, and tastes? Why is one substance
soft, another hard, and yet another fluid? From what you have read
so far, you may answer these questions saying, "The differences
between their atoms do this". Yet, this answer is not sufficient,
because if the atoms were the cause for these differences, then
there would have to be billions of atoms bearing different properties
from each other. In practice, this is not so. Many materials look
different and bear different properties although they contain the
same atoms. The reason for this is the different chemical bonds
the atoms form among them to become molecules.
On the way to matter, molecules are the second
step after atoms. Molecules are the smallest units determining the
chemical properties of matter. These small bodies are made up of
two or more atoms and some, of thousands of groups of atoms. Atoms
are held together inside molecules by chemical bonds determined
by the electromagnetic force of attraction, which means that these
bonds are formed on the basis of the electrical charges of the atoms.
The electrical charges of atoms, in turn, are determined by the
electrons on their outermost shell. The arrangement of molecules
in different combinations give rise to the diversity of matter we
see around us. The importance of the chemical bonds that lie at
the heart of the diversity of matter come forward at this very point.
As explained above, chemical bonds are formed through the motion
of electrons in the outermost electron shells of the atoms. Each
atom has a tendency to fill up its outermost shell with the maximum
number of electrons it may shelter. The maximum number of electrons
the atoms can hold in their outermost shells is 8. To do this, atoms
either receive electrons from other atoms to complete the electrons
in their outermost shells to eight, or if they have lesser electrons
in their outermost shells, then they give these to another atom,
making a sub-shell that had previously been completed in their outermost
orbits. The tendency of the atoms to exchange electrons constitutes
the basic inciting force of the chemical bonds they form between
This driving force, that is, the objective of the atoms
to raise the number of electrons in their outermost shells to maximum,
causes an atom to form three types of bonds with other atoms. These
are the ionic bond, covalent bond and metallic bond.
Commonly, special bonds categorised under the general
title of "weak bonds" act between molecules. These bonds
are weaker than the bonds formed by atoms to constitute molecules
because molecules need more flexible structures to form matter.
Let us now, in brief, see the properties of these bonds
and how they are formed.
Atoms combined by this bond swap electrons to complete the number
of electrons in their outermost shells to eight. Atoms having up
to four electrons in their outermost shells give these electrons
to the atom with which they are going to combine, that is, with
which they will bond. Atoms having more than four electrons in their
outermost shells receive electrons from the atoms with which they
will bond. Molecules formed by this type of bond have crystal (cubic)
structures. Familiar table salt (NaCl) molecules are among substances
formed by this bond. Why do atoms have such a tendency? What would
happen if they did not have it?
Until today, the bonds formed by atoms could be defined only in
very general terms. It has not yet been understood why atoms adhere
to this principle. Could it be that atoms decide by themselves that
the number of electrons in their outermost shells should be eight?
Definitely not. This is such decisive behaviour that it goes beyond
the atom, because it has no intellect, will, or consciousness. This
number is the key in the combination of atoms as molecules that
constitute the first step in the creation of the matter, and eventually,
the universe. If atoms did not have such a tendency based on this
principle, molecules, and in turn, matter would not exist. Yet,
from the first moment they were created, atoms have been serving
in the formation of molecules and matter in a perfect manner thanks
to this tendency.
Scientists who studied the bonds between atoms faced an interesting
situation. While some atoms swap electrons for bonding, some of
them share the electrons in their outermost shells. Further research
revealed that many molecules that are of critical importance for
life owe their existence to these 'covalent' bonds.
Let us give a simple example to explain covalent bonds
better. As we mentioned previously on the subject of electron shells,
atoms can carry a maximum of two electrons in their innermost electron
shells. The hydrogen atom has a single electron and it has the tendency
to increase the number of its electrons to two to become a stable
atom. Therefore, the hydrogen atom forms a covalent bond with a
second hydrogen atom. That is, the two hydrogen atoms share each
other's single electron as a second electron. Thus, the H2
molecule is formed.
If a large number of atoms come together by sharing each others'
electrons, this is called a "metallic bond". Metals like
iron, copper, zinc, aluminium, etc., that form the raw material
of many tools and instruments we see around us or use in daily life,
have acquired a substantial and tangible body as a result of the
metallic bonds formed by the atoms constituting them.
Scientists are not able to answer the question as to
why electrons in the electron shells of the atoms have such a tendency.
Living organisms, most interestingly, owe their existence to this
The Next Step:Compounds
Do you wonder how many different compounds these bonds can form?
In laboratories, new compounds are
produced everyday. Currently, it is possible to talk about almost
two million compounds. The simplest chemical compound can be as
small as the hydrogen molecule, while there are also compounds made
up of millions of atoms.1
How many different compounds can an element form at most? The answer
to this question is quite interesting because, on the one hand,
there are certain elements that do not interact with any others
(inert gases), while, on the other hand, there is the carbon atom
that is able to form 1,700,000 compounds. As stated above, the total
number of compounds is about two million. 108 elements out of the
total of 109 form 300,000 compounds. Carbon, however, forms 1,700,000
compounds all by itself in a most amazing fashion.
The BuIldIng Block of LIfe: the
Carbon is the most vital element for living beings, because all
living organisms are constructed from compounds of carbon. Numerous
pages would not be enough to describe the properties of the carbon
atom, which is extremely important for our existence. Nor has the
science of chemistry yet been able to discover all of its properties.
Here we will mention only a few of the very important properties
Structures as diverse as the cell membrane, the horns
of an elk, the trunk of a redwood, the lens of the eye, and the
venom of a spider are composed of carbon compounds. Carbon, combined
with hydrogen, oxygen, and nitrogen in many different quantities
and geometric arrangements, results in a vast assortment of materials
with vastly different properties. So, what is the reason for carbon's
ability to form approximately 1.7 million compounds?
One of the most significant properties
of carbon is its ability to form chains very easily by lining carbon
atoms up one after another. The shortest carbon chain is made up
of two carbon atoms. Despite the unavailability of an exact figure
on the number of carbons that make up the longest carbon chain,
we can talk about a chain with seventy links. If we consider that
the atom that can form the longest chain after the carbon atom is
the silicon atom forming six links, the exceptional position of
the carbon atom will be better understood.2
which is a very valuable stone, is a derivative of carbon, which
is otherwise commonly found in nature as graphite.
The reason for carbon's ability to form chains with so many links
is because its chains are not exclusively linear. Chains may be
branched, as they may also form polygons.
At this point, the form of the chain plays a very important
role. In two carbon compounds, for example, if the carbon atoms
are the same in number yet combined in different forms of chains,
two different substances are formed. The abovementioned characteristics
of the carbon atom produce molecules that are critical for life.
Some carbon compounds' molecules consist of just a
few atoms; others contain thousands or even millions. Also, no other
element is as versatile as carbon in forming molecules with such
durability and stability. To quote David Burnie in his book Life:
Carbon is a very unusual element.
Without the presence of carbon and its unusual properties, it is
unlikely that there would be life on Earth.3
Concerning the importance of carbon for living beings, the British
chemist Nevil Sidgwick writes in Chemical Elements and Their Compounds:
Carbon is unique among the elements in the number
and variety of the compounds which it can form. Over a quarter of
a million have already been isolated and described, but this gives
a very imperfect idea of its powers, since it is the basis of all
forms of living matter. 4
The class of compounds formed exclusively from carbon and hydrogen
are called "hydrocarbons". This is a huge family of compounds
that include natural gas, liquid petroleum, kerosene, and lubricating
oils. The hydrocarbons ethylene and propylene form the basis of
the petrochemical industry. Hydrocarbons like benzene, toluene,
and turpentine are familiar to anyone who's worked with paints.
The naphthalene that protects our clothes from moths is another
hydrocarbon. Hydrocarbons combined with chlorine or fluorine form
anaesthetics, the chemicals used in fire extinguishers and the Freons
used in refrigeration.
As the chemist Sidgwick stated above, the human mind
is insufficient to fully understand the potential of this atom that
has only six protons, six neutrons and six electrons. It is impossible
for even a single property of this atom, which is vital for life,
to form by chance. The carbon atom, like everything else, has been
created by Allah perfectly adapted for the bodies of living beings,
which Allah encompasses down to their very atoms.
What is in the heavens and in the earth belongs to Allah. Allah
encompasses all things. (Surat
Intermolecular Bonds: Weak Bonds
The bonds combining the atoms in molecules are much stronger than
these weak intermolecular bonds. These bonds can help the formation
of millions, and even billions of kinds of molecules.
Well, how do molecules combine to form matter?
Since molecules become stable after their formation,
they no longer swap atoms.
So, what holds them together?
Proteins have to have a special three-dimensional configuration
to perform their critical roles in our bodies. Weak bonds between
molecules form these structures.
In an effort to answer this question, chemists produced
different theories. Research showed that molecules are able to combine
in different ways depending on the properties of the atoms in their
These bonds are very important for organic chemistry,
which is the chemistry of living beings, because the most important
molecules constituting life are formed due to their ability to form
these bonds. Let us take the example of proteins. The complex three-dimensional
shapes of proteins, which are the building blocks of living things,
are formed thanks to these bonds. This means that the weak chemical
bond between molecules is at least as necessary as the strong chemical
bond between atoms for the formation of life. Certainly, the strength
of these bonds must be of a certain measure.
We can continue with the protein example. Molecules
called amino acids combine to form proteins, which are much larger
molecules. The atoms forming amino acids are combined by covalent
bonds. Weak bonds combine these amino acids in such a way as to
produce three-dimensional patterns. Proteins can function in living
organisms only if they have these three dimensional patterns. Therefore,
if these bonds did not exist, neither would the proteins, or, therefore,
The "hydrogen" bond, a type of weak bond, plays a major
role in the formation of materials that bear great importance in
our lives. For instance, the molecules forming water, which is the
basis of life, are combined by hydrogen bonds.
A MIracle Molecule:Water
A liquid specifically chosen for life - "water" - covers
two-thirds of our earth. The bodies of all living beings on the
earth are formed of this very special liquid at a ratio ranging
between 50%-95%. From bacteria living in springs with temperatures
close to the boiling point of water, to some special mosses on melting
glaciers, life is present everywhere where there is water, no matter
at what temperature. Even in a single droplet hung on a leaf after
rain, thousands of microscopic living organisms emerge, reproduce,
How would the earth look if there were no water? Certainly,
everywhere there would be desert. There would be abysses and horrific
pits, in place of seas. The sky would seem cloudless and have a
In fact, it is extremely difficult for water, the basis
of life on earth, to form. First, let us imagine that hydrogen and
oxygen molecules, which are the components of water, are put in
a glass bowl. Let us leave them in the bowl for a very long time.
These gases may still not form water even if they remain in the
bowl for hundreds of years. Even if they do, it would not be more
than a very small amount at the very bottom of the bowl and that
would happen in a very slow fashion, maybe over thousands of years.
The reason why water forms so slowly under these circumstances
is temperature. At room temperature, oxygen and hydrogen react very
If water did not have the property of freezing from the surface
downwards, a major portion of the seas would be frozen within
a year and life in the sea would be endangered.
Oxygen and hydrogen, when free, are found as H2
and O2 molecules. To combine to form the water molecule,
they must collide. As a result of this collision, the bonds forming
the hydrogen and oxygen molecules weaken, leaving no hindrance for
the combination of oxygen and hydrogen atoms. Temperature raises
the energy and therefore, the speed of these molecules, resulting
in an increase in the number of collisions. Thus, it accelerates
the course of the reaction. However, currently, no temperature high
enough to form water exists on earth. The heat required for the
formation of water was supplied during the formation of the earth,
which resulted in the emergence of so much water as to cover three
quarters of the earth's urface. At present, water evaporates and
rises to the atmosphere where it cools and returns to the earth
in the form of rain. That is, there is no increase in the quantity;
only a perpetual cycle.
The MIraculous PropertIes of
Water has many exceptional chemical properties. Every water molecule
forms by the combination of hydrogen and oxygen atoms. It is quite
interesting that these two gases, one combustive and the other combustible,
combine to form a liquid, and most interestingly, water.
Now, let us briefly see how water is formed chemically.
The electrical charge of water is zero, that is, it is neutral.
Yet, due to the sizes of the oxygen and hydrogen atoms, the oxygen
component of the water molecule has a slightly negative charge and
its hydrogen component has a slightly positive charge. When more
than one water molecule come together, positive and negative charges
attract each other to form a very special bond called "the
hydrogen bond". The hydrogen bond is a very weak bond and it
is incomprehensibly short-lived. The duration of a hydrogen bond
is approximately one hundred billionth of a second. But as soon
as a bond breaks, another one forms. Thus, water molecules adhere
tightly to each other while also retaining their liquid form because
they are combined with a weak bond.
Hydrogen bonds also enable water to resist temperature
changes. Even if air temperature increases suddenly, water temperature
increases slowly and, similarly, if air temperature falls suddenly,
water temperature drops slowly. Large temperature changes are needed
to cause considerable changes in water temperature. The significantly
high thermal energy of water has major benefits for life. To give
a simple example, there is a great amount of water in our bodies.
If water adapted to the sudden vicissitudes of temperature in the
air at the same rate, we would suddenly develop fevers or freeze.
By the same token, water needs a huge thermal energy to evaporate.
Since water uses up a great deal of thermal energy while evaporating,
its temperature drops. To give an example, again from the human
body, the normal temperature of the body is 360 C and the highest
body temperature we can tolerate is 420 C. This 60 C interval is
indeed very small and even working under the sun for a few hours
can increase body temperature by that amount. Yet, our bodies spend
a great amount of thermal energy through sweating, that is, by causing
the water it contains to evaporate, which in turn causes body temperature
to drop. If our bodies did not have such an automatic mechanism,
working for even a few hours under the sun could be fatal.
Hydrogen bonds equip water with yet another extraordinary property,
which is water's being more viscous in its liquid state than in
its solid state. As a matter of fact, most substances on earth are
more viscous in their solid states than in their liquid states.
Contrary to other substances, however, water expands as it freezes.
This is because hydrogen bonds prevent water molecules from bonding
to each other too tightly, and thus many gaps are left in between
them. Hydrogen bonds are broken down when water is in liquid state,
which causes oxygen atoms to come closer to each other and form
a more viscous structure.
This also causes ice to be lighter than water. Normally, if you
melt any metal and throw in it a few solid pieces of the same metal,
these pieces would sink directly to the bottom. In water, however,
things are different. Icebergs weighing ten thousands of tons float
on water like corks. So, what benefit can this property of water
Let us answer this question with the example of a river:
When the weather is very cold, it is not the whole river, but only
the surface of it that freezes. Water reaches its heaviest state
at + 40° C, and as soon as it reaches this temperature, it immediately
sinks to the bottom. Ice is formed on top of water as a layer. Under
this layer, water continues to flow, and since + 40°C is a temperature
at which living organisms can survive, life in water continues.
These unique properties which Allah has given water make life possible
on the earth. In the Qur'an, Allah states the importance of this
great blessing He offers man:
It is He Who sends down water from the sky.
From it you drink and from it come the shrubs among which you graze
your herds. And by it He makes crops grow for you and olives and
dates and grapes and fruit of every kind. There is certainly a Sign
in that for people who reflect. (Surat
L. Vlasov, D. Trifonov, 107 Stories About Chemistry, 1977, p. 117
2. L. Vlasov, D. Trifonov, 107 Stories About Chemistry, 1977, p. 118
3. David Burnie, Life, Eyewitness Science, London: Dorling Kindersley,
4. Nevil V. Sidgwick, The Chemical Elements and Their Compounds, vol.1,
Oxford: Oxford University Press, 1950, p.490