General Chemistry

1. DALTON’S ATOMIC
THEORY

2. JOHN DALTON’S ATOMIC THEORY OF
MATTER
Lavoiser’s law of conservation of
mass and Proust’s law of definite
proportions were repeatedly verified by
experiment. This work led to attempts
to develop theories to explain these
laws. This theory is based on the three
laws of matter.

3. JOHN DALTON’S ATOMIC THEORY OF
MATTER
By using experimental methods,
John Dalton (1766-1844), a chemist
and school teacher in England, revived
and revised Democritus’ ideas and
turned them into a scientific theory.

4. JOHN DALTON’S ATOMIC THEORY OF
MATTER
Dalton’s atomic theory is based on these postulates;
1. Elements are composed of small particles called atoms.
2. Atoms of an element are identical, having the same properties
such as mass, size, and chemical properties.
3. Compounds are composed of atoms of at least two different
elements, and the ratio of each element is an integer or a simple
fraction. For example, carbon dioxide has 1 carbon atom and 2
oxygen atoms, and their ratio is 1 is to 2.
4. A chemical reaction results from the rearrangement of the atoms
of reacting substances, giving new combinations of atoms. Atoms
can neither be destroyed nor created in a chemical reaction.

5. ASSESSMENT
Using the three laws of matter,
explain each of Dalton’s postulate.
Explain your answer.