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DALTONS ATOMIC THEORY

In 1808 John Dalton proposed the following Atomic theory.

  1. All elements are made up of small indivisible particles called atoms.
  2. Atoms can neither be created or destroyed
  3. Atoms of the same element are alike in every aspect, and differ from atoms of all other elements.
  4. When atoms combine with other atoms, they do so in simple ratios.
  5. All chemical changes result from the combination or the separation of atoms.

      MODIFICATIONS OF DALTON’S ATOMIC THEORY

The following are the modifications to Dalton’s atomic theory.

  1. All matter is made up of small particles, protons, neutrons and electrons.
  2. An atom can be destroyed and created; when radioactive atoms disintegrate with the emission of particles, new atoms are produced.
  3. The atoms of the same elements are not all alike, but may have different masses as proved by the phenomenon of isotopy.
  4. In large organic molecules, such as proteins, fats and starch, the combining ratio are in large whole number.

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