Presented by: Nihal Lashin
Omar Sarwat
Mohamed Sadek
General Knowledge about atoms
 “All things are made of atoms” the great Caltech
physicist Richard Feynman.
 The basic working arrangements of atoms is the
 What is a molecule?
 Chemists way of thinking:
Molecules Vs Elements
 Properties of an atom:
1. Tiny
2. Durable
Long lived (10ˆ35 )
3. Everywhere
4. Numerous
5. Recycled
6. Indestructible
The size of an atom:
 If you want to see a paramecium- a single celled, fresh
water creature which is about 0.002 mm, you have to
enlarge it 12 meters across
 If you want to see an atom in a drop of water you have to
enlarge the drop 24 kilometers across
***Can you see how small it is???
 The scale of an atom: One ten-millionth of a millimeter.
History of atoms:
 First the idea of atoms developed by the ancient
 Dalton’s contribution:
Relative size of an atom
2. Characters of atoms
3. How atoms fit together
The Viennese physicist
Ernest Mach doubted
the existence of atoms…
“Atoms cannot be
perceived by the senses…
they are things of
thought” he wrote.
• The first real hero of the
atomic age is Ernest
 He received a Nobel Prize for investigations into
disintegration of the element.
 In Manchester University, he did his most important
work in determining the structure and the nature of
the atom.
 In 1910 he invented the radiation detector.
 An atom according to Rutherford was an empty space
with a very dense nucleus at the centre.
 In 1897 J.J. Thomson discovered
the electron
 In 1911 C. T. R. Wilson produced
the first particle detector.
 In 1932 James Chadwick
discovered the neutron.
The Atom Revealed
• In 1910, Rutherford and his assistant Hans Geiger
conducted an Experiment which revealed the internal
structure of an atom.
• We will add some more points after the video to further illustrate the
experiment and its conclusion.
The structure of an atom as we know now:
 It’s made of three things:
Protons which have a positive charge
Electros which have a negative charge
Neutrons which have no charge
 Protons and neutrons are packed inside of the
nucleus, while electrons spin around outside.
** Protons give an atom its
identity, while neutrons
add to its mass.

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