Question

write down the merit and demerit of Dalton Atomic Theory

Answer 1

Merits of Dalton’s atomic theory :- 
• It has enabled us to explain the laws of chemical combination, which states that every compound consist elements in definite proportion by weight.

• Dalton was the first person to recognize a workable distinction between the ultimate particle of an element (atom) and that of a compound (molecule)


Drawbacks of Dalton’s atomic theory of matter
• An atom is no more be considered as indivisible and can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions.

• According to Dalton, the atoms of same element are similar in all respects. However, atoms of some elements vary in their masses and densities. These atoms of different masses are called isotopes. For example, carbon has two isotopes with mass numbers 12 and 14.

• Dalton also claimed that atoms of different elements are different in all respects. This has been proven wrong in certain cases as in isobars, which are different in atomic no. But has same mass no. e.g. argon and calcium atoms each have an atomic mass of 40 amu.

• According to Dalton, atoms of different elements combine in simple whole number ratios to form compounds. This is not observed in complex organic compounds like sugar (C12H22O11).

• The theory fails to explain the existence of allotropes; it does not account for differences in properties of charcoal, graphite, diamond.

Answer 2

Drawbacks of Dalton's Atomic Theory. The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions. According toDalton, the atoms of same element are similar in all respects