Transcript Presentation 2.4

DALTON’S ATOMIC THEORY
Haley, Josh, Austin
WHO WAS HE?
John Dalton (1766-1844) developed an atomic theory that proposed that
atoms were responsible for the combinations of elements found in
compounds.
DALTONS ATOMIC THEORY
All matter is made up of tiny particles called atoms (true)
All atoms of a given element are identical to one another and different from
atoms of other elements(false)
Atoms of two or more different elements combine to form compounds. A
Particular compound is always made up of the same kinds of atoms and the
same number of each kind of atom (true)
A chemical reaction involves the rearrangement, separation, or combination
of atoms. Atoms are never created or destroyed during a chemical reaction.
(true/false)
Atoms of different elements have different weights and different chemical
properties. (true)
EXPERIMENTS TESTED BY
DALTON
John Dalton found that things combine in different proportions over and over
again. Daltons atomic theory
Dalton burnt wood and oxygen and then it turned into ashes, carbon dioxide
and water vapor. The mass of wood and oxygen equal the mass of the ashes,
carbon dioxide and water vapor.
One carbon atom+ four hydrogen atoms- CH4
WHERE DOES HIS THEORY FIT IN
THE TIME LINE OF HISTORY?
• Dalton was the first to use the scientific method to create a theory
involving atoms.
• His atomic theory was proposed in 1803, hundreds of years after Aristotle
first researched atoms.
HOW HAS HIS THEORY HELD UP
OVER TIME?
• Two of his postulates have been proven wrong
• These two include, All atoms of a given element are identical to one
another and different from atoms of other elements & A chemical reaction
involves the rearrangement, separation, or combination of atoms. Atoms
are never created or destroyed during a chemical reaction
• Although these two were proven false, the remaining three postulate
remain accurate.