Download Atomic Structure

Atomic Structure
Matter: anything that has a mass
BUT…. What is matter made up of?
AND
Where did matter come from?
Matter is made up of atoms. Atoms are
made up of protons, neutrons and
electrons.
Hypothesis –
First Models Of Matter
There were many scientist that
contribute to the development of the
first models of matter
1. Aristotle
4. J.J. Thomson
2. Democritus
5. Rutherford
3. John Dalton
6. Bohr
Aristotle: Philosopher 300 BC (Greek)
HE PROPOSED THAT:
 All matter was continuous –no matter how
small a substance was, the original
properties were the same.
 Matter was made of the four basic elements
fire, water, air, earth.
 Did not know about atoms.
Democritus: Philosopher 300 BC (Greek)
HE PROPOSED THAT:
 Matter was discontinuous
 Matter can be broken into smaller
particles
 Defined the term atom
First Models
• Despite Democritus’ accuracy,
Aristotle’s ideas were more widely
accepted.
• Neither man was a scientist and
neither did any experiments.
• They were both thinkers and
came up with ideas to explain
what they saw in the world
around them.
Developed by John Dalton


He is known as the father of the Atomic
Theory.
He formulated four main points concerning
atoms:
Memorize
1) All matter is composed of tiny
indivisible particle called atoms.
2) All atoms of the same element are
identical (same).
3) Atoms of different elements are
different.
4) During a chemical reaction atoms
combine to form new products.
Dalton’s Atomic Model


Even today, basic principles of
his theory are still true.
His model was modified to
explain new observations of
later chemists
WHO SAID THE FOLLOWING?
“Matter
“All matter
can be
is broken
made of
into
smaller
earth, fire,
particles”
air or water”
“No“Atoms
matter of
how
small a substance
different
was,
the original
elements
are properties
different are the
same”
 Original Theories
• Discontinuous (Democritis) – spaces
between particles
• Continuous (Aristotle) – no spaces
between particles. Four elements –
fire, water, earth & air.
• Dalton’s Theory – memorize 4 main
points