Ideas about Atoms
By
Kürşat Keleşoğlu
Democritus

The theory of Democritus and
Leucippus held everything to
be composed of atoms, which
are physically, but not
geometrically, indivisible; that
between atoms lies empty
space; that atoms are
indestructible; have always
been, and always will be, in
motion; that there are an
infinite number of atoms, and
kinds of atoms, which differ in
shape, and size
Elements are made up of
indivisible and
undestructable so little
particles.
 Chemical reactions are
results of seperating or
combining atoms.
 Atoms come together and
form molecules.
 Molecules of one compound
are the same

John Dalton


Experiments by J.J. Thomson in 1897 led to the discovery
of a fundamental building block of matter.
In Thomson's model, electrons were free to rotate in rings
which were further stabilized by interactions between the
electrons, and spectra were to be accounted for by energy
differences of different ring orbits.
J. J. Thompson

The mathematical model of Brownian
motion has several real-world
applications.
Brownian Motion Theory
Ernest Rutherford

Ernest Rutherford publishes his atomic
theory describing the atom as having a
central positive nucleus surrounded by
negative orbiting electrons. This model
suggested that most of the mass of the
atom was contained in the small nucleus,
and that the rest of the atom was mostly
empty space but J. Thomson considered
that the structure of an atom is something
like a raisin bread, so that his atomic
model is sometimes called the raisin
bread model. He assumed that the basic
body of an atom is a spherical object
containing N electrons confined in
homogeneous jellylike but relatively
massive positive charge distribution whose
total charge cancels that of the N
electrons.
Alpha-particle scattering

The Geiger–Marsden experiment (also
called the Gold foil experiment or the
Rutherford experiment) was an
experiment to probe the structure of
the atom performed by Hans Geiger
and Ernest Marsden in 1909. The
unexpected results of the experiment
demonstrated for the first time the
existence of the atomic nucleus,
leading to the downfall of the plum
pudding model of the atom, and the
development of the Rutherford (or
planetary) model.
James Chadwick
In 1932 Chadwick heard of a new method of detecting particles emitted by
radioactive elements developed by Irene Joliot-Curie, one of Marie Curie's
daughters, and her husband, Frederic. He used this new technique and
discovered that there were different particles in the nucleus which were
neutrally charged.These particles became known as neutrons and
revolutionised the study of radioactive elements. Soon after this, neutrons
were used to bombard uranium atoms, which lead to the discovery of
nuclear fission and the development of both the atomic bomb and nuclear
power.
 Because proton numbers of the atoms of the same element are the same
so we need to have difference between atoms of the same elements.
When we see neutron numbers are different in the atoms of the same
element we see that isotopes exists.

Quarks

In physics, the quark model is a
classification scheme for hadrons
in terms of their valence quarks—
the quarks and anti-quarks which
give rise to the quantum numbers
of the hadrons