Essay on Chemistry

This essay has a total of 924 words and 4 pages.


The History Behind The Atom

Throughout the discovery of the atom, many scientists worked to formulate how the atom
works. Which began in the early 1800’s with John Dalton, to our current model of the
electron cloud developed by Schrodinger. During this long process of the discovery the
atom, took many models and scientists. The entire group of scientists who assisted in the
discovery of the atom used each other’s model to improve each other’s theories.

Firstly, John Dalton showed that, collectively, the three laws, the law of definite
proportion, the law of conversation of masses, and the law of multiple proportion. These
three laws demonstrate the existence of the atom. Also, Using these three laws he
developed a theory called, Dalton’s Atomic Theory. This includes five basic principles;
1) all matter is made of indivisible and indestructible atoms, 2) atoms of a given element
are identical in their physical and chemical properties, 3) atoms of different elements
have different physical and chemical properties, 4) atoms of different elements combine in
simple whole-number ratios to form chemical compounds, 5) atoms cannot be subdivided,
created or destroyed when they are combined, separated, or rearranged in chemical
reactions. However, after scientists look more carefully at his points they found some
weaknesses. One weakness was that the atom was found to be indivisible, and they had
smaller particles.

After Dalton came up with the five points, J.J. Thompson came along. He discovered that
charged and magnets deflected the straight paths of cathode rays. In addition, he
discovered negative and positive charged particles. He stated that the atom was made of
smaller particles called, electrons and protons. In the discovery of the electron he used
the Cathode-ray tube. As he researched he came up with a model of the atom, he stated
that the atom was a “plum pudding model.” This model featured negatively charged
electrons embedded in a ball of positive charge.

After, J.J. Thompson came Ernst Rutherford, who was a student of Mr. Thompson. He created
“gold-foil experiment” which untimely-disproved J.J. Thompson’s theory. In this
experiment he directed a beam of alpha particles at a very thin gold foil sheet. This was
so the Rutherford could measure the angles of the particles coming off the gold foil.
Sheet. Most of the alpha particles went through the sheet, however some of the particles
hit the foil and bounced back. The reason of this was that the particles that bounced off
the nucleus and the particles that went straight through traveled in the empty space. The
major was that his experiment was that the atom would eventually lose its energy and
collapse in the nucleus.

Around 1913, a Danish physicist named Niels Bohr came up with a new model to further our
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