3. 1844) was an
English chemist, meteorologist and p
hysicist. He is best known for his
pioneering work in John Dalton (6
September-1766 – 27 July the
development of modern atomic
theory, and his research into colour
blindness
4. In 1800, Dalton became a secretary of
the Manchester Literary and
Philosophical Society, and in the
following year he orally presented an
important series of papers, entitled
"Experimental Essays" on the
constitution of mixed gases; on
the pressure of steam and
other vapours at different
temperatures, both in a vacuum and
in air; on evaporation; and on
the thermal expansionof gases. These
four essays were published in
the Memoirs of the Lit & Phil in 1802
5. Postulates of Dalton's atomic
theory
Elements are made of extremely small
particles called atoms.
Atoms of a given element are identical
in size, mass, and other properties;
atoms of different elements differ in
size, mass, and other properties.
Atoms cannot be subdivided, created,
or destroyed.
Atoms of different elements combine in
simple whole-number ratios to
form chemical compounds.
In chemical reactions, atoms are
combined, separated, or rearranged.
