Question

Discovery of isotopes and isobars contradict some of the postulates of ___ atomic theory.
A. Bohr's
B. Dalton's
C. Rutherford's
D. Thomson's

Answer 1

Discovery of isotopes and isobars contradict some of the postulates of ___ atomic theory.

Answer is : Dalton's Atomic theory

Explanation

1. Isotopes are the atoms of same elements having same atomic number but different mass number due to difference in neutrons.

eg : ¹²c₆,¹³c₆, ¹⁴c₆

2.Isobars are atoms of different elements having same mass number .

example : ⁴⁰Ar₁₈ and ⁴⁰ Ca₂₀

Which contradicts the following postulate of Dalton's Theory:

"Atoms of same elements are identical that is similar in mass and shape.

and atoms of different elements  are different in all aspects ."

Answer 2

1. Isotopes are the particles of same components having same nuclear number yet unique mass number because of distinction in neutrons.eg : ¹²c₆,¹³c₆, ¹⁴c₆ 2.

Isobars are molecules of various components having same mass number.

"Molecules of same components are indistinguishable that is comparative fit as a fiddle and particles of various components are distinctive in all viewpoints."