Transcript Atomic Models

Atomic Models
Chemistry
Why is Lego™ the most
ingenious toy in the world?
Excerpt from Sophie’s World©
By Jostein Gaarder
Models
Empedocles, ~450 BC
 Democritus, 400 BC
 John Dalton, ~1800
 Thomson Model, 1904
 Nagaoka / Rutherford Model, 1911
 Robert Milliken
 Bohr Model, 1913
 Schrodinger’s Model, 1925

Why?
Empedocles, ~450 BC
Earth, Air, Fire, Water
 Love and Strife changes the elements

– Love unites elements
– Strife drives elements apart

Aristotle called him “The Father of
Rhetoric”
Democritus
(~400 BC)
The Happy Philosopher
 “Atomos”-cannot be divided
 “The Void”
 Nothing exists except atoms and empty
space; everything else is opinion.

Democritus
(~400 BC)

Nothing
exists except
atoms and
empty space;
everything
else is
opinion.
John Dalton
1766 – 1844
 English, Born a Quaker and the son of a
weaver
 Did research on color blindness, atomic
theory, gasses, atomic weights, meteorology
 Proposed a version of the periodic table
 Proposed Dalton’s Atomic Theory

John Dalton

Proposed a version
of the periodic
table
Dalton’s Atomic Theory
1.
2.
3.
4.
5.
Elements are made of tiny particles called atoms
All atoms of a given element are identical
The atoms of a given element are different from
those of any other element
Atoms of one element can combine with atoms of
other elements to form compounds. A given
compound always has the same relative numbers
and types of atoms (The Law of Constant
Composition).
Atoms are indivisible in chemical processes. That
is, atoms are not created or destroyed in chemical
reactions. A chemical reaction simply changes the
way atoms are grouped together.
- 1897
- 1897
Hantaro Nagaoka
1904



Japanese physicist from Nagasaki
Suggested that an atom has a central nucleus to
which electrons orbit like the rings of saturn.
This is the “Typical” model initially used to
describe the atom
Ernest Rutherford
1871 - 1937
Ernest Rutherford's family emigrated
from England to New Zealand before
he was born. They ran a successful
farm near Nelson, where Ernest was
born. One of 12 children, he liked the
hard work and open air of farming, but
was a good student and won a
university scholarship. After college, he
won another scholarship to study at
Cambridge University in England -- a
turning point in his life. There he met
J.J. Thomson (who would soon
discover the electron), and Thomson
encouraged him to study recentlydiscovered x-rays.
Rutherford reasoned that
all of the atoms positively
charged particles were
contained in the nucleus.
The negatively charged
electrons were scattered
outside the nucleus around
the atoms edge.
Robert Millikan
1910 (1913)

Determined the charge and energy of the
electron.
+
-
Niels Bohr

Model of the atomic structure,1913
Louis De Broglie
1924
French physicist
 Proposed that electrons have some
properties of waves based on work by
Einstein and Planck (Wave-Particle
duality duality of light).

Erwin Schrodinger
1925
The Founder of Quantum Wave
Mechanics
 Determined an equation to determine
the location of an electron based upon
probability
 Credited for development of the
Quantum Mechanical Model of the
atom

Models
Empedocles, ~450 BC
 Democritus, 400 BC
 John Dalton, ~1800
 Thomson Model, 1904
 Nagaoka / Rutherford Model, 1911
 Robert Milliken
 Bohr Model, 1913
 Schrodinger’s Model, 1925
