The incorrect postulates of the Dalton's atomic theory are :

Incorrect Postulates of Dalton's Atomic Theory | JEE Mains PYQ | Structure of Atom

Q. The incorrect postulates of the Dalton's atomic theory are :

(A) Atoms of different elements differ in mass.

(B) Matter consists of divisible atoms.

(D) All the atoms of given element have different properties including mass.

(E) Chemical reactions involve reorganisation of atoms.

Choose the correct answer from the options given below :

(A) (B), (D) only

(B) (A), (B), (D) only

(D) (C), (D), (E) only

Explanation

Statement (A)

Atoms of different elements differ in mass – this is a correct postulate.

Statement (B)

Dalton stated atoms are indivisible, but modern science shows atoms are divisible (protons, neutrons, electrons). Hence this statement is incorrect.

Statement (C)

Compounds are formed in fixed ratios – this is a correct postulate.

Statement (D)

Dalton stated atoms of the same element have identical properties, but isotopes exist. Hence this statement is incorrect.

Statement (E)

Chemical reactions involve reorganisation of atoms – this is a correct postulate.

Correct Answer = (B), (D) only

Previous Year Questions – Structure of Atom

The value of Rydberg constant (RH) is 2.18 × 10−18 J. The velocity of electron having mass 9.1 × 10−31 kg in Bohr's first orbit of hydrogen atom is ______ × 105 m s−1.

In an atom, total number of electrons having quantum numbers n = 4, mₗ = 1 and mₛ = −1/2 is ______.

For hydrogen atom, energy of an electron in first excited state is −3.4 eV. K.E. of the same electron of hydrogen atom is x eV. Value of x is ______ × 10−1 eV.

Frequency of the de-Broglie wave of electron in Bohr's first orbit of hydrogen atom is ______ × 10¹³ Hz.

Given below are two statements related to Heisenberg uncertainty principle. Choose the correct answer.

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