Question

In Bohr's model of atom:
This question has multiple correct options
A) electrons revolve around the nucleus in circular orbits
B) these circular orbits or shells are stationary
C) each shell in associated with a definite amount of energy
D) all shells have equal energy level

Answer 1

To answer this question, you must remember the concept of Bohr’s Atomic Model. Enlist all the postulates one by one and then conclude the correct options using the postulates.

Complete answer: Step 1: Enlist all the postulates of Bohr’s Atomic model and then you will be able to answer the question:
-Postulate 1: Electrons revolve around the nucleus in a fixed circular path termed “orbits” or “shells” or “energy level.”
-Postulate 2: The orbits are termed as “stationary orbit.”
-Postulate 3: Every circular orbit will have a certain amount of fixed energy and these circular orbits were termed orbital shells. The electrons will not radiate energy as long as they continue to revolve around the nucleus in the fixed orbital shells.
-Postulate 4: The different energy levels are denoted by integers such as n=1 or n=2 or n=3 and so on. These are called quantum numbers. The range of quantum numbers may vary and begin from the lowest energy level (nucleus side n=1) to highest energy level. Learn the concept of an Atomic number here.
-Postulate 5: The different energy levels or orbits are represented in two ways such as 1, 2, 3, 4… or K, L, M, N….. shells. The lowest energy level of the electron is called the ground state. Learn the concept of Valency here in detail here.
-Postulate 6: The change in energy occurs when the electrons jump from one energy level to another. In an atom, the electrons move from lower to higher energy level by acquiring the required energy. However, when an electron loses energy it moves from higher to lower energy level.
Step 2: By going through all these postulates, we can easily conclude that:

Therefore the correct options are A,B,C.

Note: The electrons move around in a predictable path called orbits. Bohr modified Rutherford’s model where he explained that electrons move around in fixed orbital shells. Furthermore, he explained that each orbital shell has fixed energy levels. Therefore, Rutherford basically explained a nucleus of an atom whereas Bohr took the model one step ahead. He explained about electrons and the different energy levels associated with it.