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Who Discovered Atomic Structure
Democritus was a Greek philosopher who lived around, 460 BC. He was the first to think up the atom, he
even gave it the name `atom' meaning `indivisible'. He believed that if you cut something in half again and
again you would soon have to stop; this matter is what he called atoms. Democritus thought atoms would
last forever and never change and could not be destroyed.
An English scientist John Dalton used Democritus original idea to come up with his own. He believe that:
All matter is formed as atoms
The atoms are indivisible and invisible particles
The atoms of the same element are the same type and mass
Atoms are rearrange in a chemical reaction
Compounds are formed when 2 or more different kinds of atoms join together
Dalton saw the atom as the basic unit of an element that can take part in chemical combination. Dalton's
discoveries showed a realistic side to the various laws of chemical combination that were around at the
time. He brought the science of atoms down to a logical level. His discoveries, even though there were
mistakes, paved the way into other scientist to explore it further. He came up with the basic laws of atoms
that we still use today
Sir JJ Thompson used an experiment called the Cathode Ray Experiments to establish electrons (e-). He
found out that from the experiment that the emitted ray was formed by negative charges, because they were
attracted by a positive pole. He came up with the theory that atoms were electrically neutral. So that meant
that the atom had to have an equal amount of negative and positive charges. The negative charges he name
electrons. He also came up with the first atomic model. Thompson described it as positively-charged sphere
in which electrons were inlaid (with negative charges). He gave science the electron. He basically came up with
the idea of how atoms worked. He even gave the first atomic model, this gives the chance for other scientist
to develop on it and improve on it.
Lord Rutherford suggested that the positive charges weren't the atom but they were in
the atom, in the nucleus, surrounded by electrons (e-). He used the Geiger-Marsden Experiment to show this.
The Geiger-Marsden experiment used alpha radiation from helium to hit very
thin gold sheets. The gold sheets were surrounded by a Zinc Sulphide
lampshade that produced visible light when hit by alpha emission. This
experiment stumbled along the discovery of isotopes.
Bohr further developed Rutherford's accidental discovery of the nuclear
atom. He used experimental evidence to support the idea of shells around the nucleus of an atom. These
are called electron orbits.
This model is well understood. Modern science has moved on by saying Atoms are not elementary particles
because they are made up of subatomic particles like protons, neutrons, quarks etc. Every scientist ideas
have really helped become to a proper understanding of atoms. At the very least each one the points each
of them made ended up to be part of what we know now.
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I used this source because it a simple version of a complex article. Most people don't trust Wikipedia but I
didn't just use that, I used other websites to back up the information I have found on Wikipedia
I used this source because it was specifically written for GCSE course and my particular course. It has also
been proven that it is a trustworthy source
I used this source because it is trustworthy. It is the royal society of chemistry.…read more