Question

The first use of quantum theory to explain the structure of atom was made by: -
A.Heisenberg
B.Bohr
C.Planck
D.Einstein

Answer 1

** This is the one which has its theory containing quantization of angular momentum and this theory gave ideas about quantum numbers. This information could easily take to the answer if analyzed properly.

Complete step by step answer:
-In the given question, Structure of atoms has been asked which used quantum theory and explained its theory on the basis of that. So, we will discuss each given option and conclude the answer.
-This was the Bohr’s theory given by Niels Bohr which gave structure of atoms on the basis of quantum theory and he took the help of Planck’s theory which stated that light is emitted or absorbed in the form of electromagnetic radiation called quantum.
-Then Bohr gave the final model which was a modified model of Rutherford’s model of atom. Some of the main highlights of Bohr theory are: -
-Atom consists of a small nucleus in the center and electrons revolve around it in a fixed orbit.
-Each orbit or shell has fixed energy which is called as orbit shells.
-The energy levels are represented by quantum numbers.
-Angular momentum of an electron is quantized
-Electrons move from lower to higher states by gaining the energy and come to the lower state by losing the energy.
-So, these were the few highlights of Bohr’s theory.
-If we look at the other options, the first one is Heisenberg which gives uncertainty principle which states that position and momentum cannot be determined simultaneously.
Planck gave its quantum theory which Bohr modified and used in its theory
Einstein gave the photoelectric effect.

So, among all the options, B is the correct option i.e. Bohr theory.

Note:
To answer similar types of questions, you must be well aware of how the theory and development of the structure of atoms started i.e. from Dalton theory to Bohr theory and few important models like Rutherford, Thomson’s etc.