Download What is an atom? What are atoms made up from? Do we really touch

What is an atom? What are atoms made up from? Do we really touch matter?
Basically, everything around us consists of atoms; every matter is made up of atoms.
In other words atoms of different elements combine to make up matter. In the 5th
century B.C. the Greek philosophers Democritus and Leucippus proposed that matter
was made up of tiny, indivisible particles they called atom, the word “atom” means
“indivisible” in Greek. The reason for this assumption is that nothing can come from
nothing. Essentially, atoms where thought to be indivisible, but due to the hard work
and determination of the scientists such as (John Dalton, Thompson, Bohr and many
more), atoms are known today to be made up of even smaller indivisible subatomic
particles.
In the first decade of the 18th century, John Dalton, was one of the first scientists who
generally contributed in developing the current understanding of atoms. Dalton
proposed the first modern atomic theory. Dalton's theory basically consisted of five
main points. Dalton reasoned: 1) Atoms combine in different ways to form matter. 2)
For a given element, all of its atoms are indistinguishable in its properties and mass.
Whereas they differ in mass and characteristics for atoms of different elements. 3)
Atoms are indivisible; they cannot be created nor destroyed. 4) In chemical reactions,
atoms of the same or different elements can be combined. 5) In chemical reactions,
these small particles combine with each other in simple, whole number ratios to form
combined atoms. His theory formed the bases of modern chemistry. Although, Some
parts of the theory were proven wrong, however, scientists kept updating it over the
years.
Atoms were thought to be the smallest particles of matter until Thomson discovered
the electrons while he was working with cathode rays. The experiment that he
conducted consisted of a tube that is a confined glass container, and there are two
electrodes that are kept apart by a vacuum medium. A current was passed across the
electrodes; cathode rays are generated, creating a glowing patch where they hit the
opposite sides of the tube. During the tests, he observed that the electric field has
been reflecting the cathode rays. He concluded that these rays, rather than being a
form of light, were composed of a nearly weightless, negatively charged particles that
he called “electrons”. His model was widely known by the plum-pudding atom, where
the structure of the atom was thought to be made of a sphere with positive charge
“pudding” and negative charges sprinkled all over the sphere just like the “plum”.
However, this model was proven wrong by one of the bright scientists.
An English chemist and physicist Ernest Rutherford who was known as “the father of
nuclear” wanted to prove Thomson’s plum pudding model by conducting an
experiment. The results that Rutherford got from the experiment proved Thomson’s
model to be incorrect. Rutherford’s experiment is known as “The gold foil experiment”,
where he aimed a beam of alpha particles (heavy, positively charged particles) at a
gold foil, surrounding the gold foil was a fluorescent screen that would glow when the
particles collide on the screen. Rutherford reasoned that the way the alpha particle
travel through out the gold foil would provide him with information regarding the
structure of the gold atoms. While conducting the experiment, he observed that most of
the alpha particles passed the gold foil without any degree of deflection, he also
noticed that a few alpha particles where deflected at different angles, and some where
reflected backwards as well. Rutherford concluded from these observations that the
atom is mostly consisted of empty space since the positively charged particles
travelled through the gold foil without a deflection, regarding the small portion of alpha
particles that were deflected and reflected, he concluded that an atom must have a
center that contains most of the atoms weight with a positive charged particles, that he
called as “protons”, which was responsible for the deflections that happened. The
atomic structure is nowadays known and accepted by the science community to
consist of a center of positive charge and it accounts for most of the atoms weight,
there are two subatomic particles in the nucleus, which are the proton and neutrons.
The protons are positively charged particles and the neutrons are neutral particles, and
the electrons which have a negative charge revolve around the nucleus in orbitals.
A cool fact about atoms, we actually don’t touch anything, because all electrons have
negative charges, and negatives repulse negatives (magnetically), at a subatomic level
we actually never touch anything. The part of the atom that contains mass, the nucleus,
never touches another nucleus. The electromagnetic force between atoms keeps the
nucleus's from ever touching. For example: The electrons in your fingertips repel the
electrons in the keyboard keys allowing the key to be pressed.
To sum up, knowing the structure of an atom is crucial especially to chemists; a lot of
phenomena’s can only be explained by understanding the structure of an atom.
Thanks to those scientists who participated in improving the atomic theory, which
made our lives easier and clearer.
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Takada, K. (2004, May 15). Discovery of atoms. Retrieved from
http://www.kutl.kyushuu.ac.jp/seminar/MicroWorld1_E/Part1_E/P12_E/DiscoverAtom_E.htm
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Atomic theory. (n.d.). Retrieved from http://www.scienceclarified.com/As-Bi/Atomic-
Theory.html
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The atom in history. (n.d.). Retrieved from
http://misterguch.brinkster.net/atomictheory.html
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The gold foil experiment. (n.d.). Retrieved from
http://myweb.usf.edu/~mhight/goldfoil.html