Chapter 28, Problem 48A

To determine

To Compare: The quantum mechanical theory of the atom with the Bohr model.

Explanation of Solution

Introduction:

The quantum theory explains the failures of Bohr’s atomic model such as fine structure of spectral lines, Zeeman and Stark’s effect and also the dual nature of electron and many more.

According to Bohr model of the atom:

• The electrons revolve around the nucleus in fixed energy orbits. In a stable orbit, an electron does not radiate energy, even though it is accelerating.
• Bohr assumed electrons as particles positioned at a definite distance from the nucleus and have a definite velocity.
• Bohr’s model was limited to the hydrogen atom, and did not allow calculation for other elements.

The quantum theory contradicts the Bohr’s theory by stating that

• The atom’s energy has only specific, quantized values.
• The model predicts the probability of finding an electron in a specific region in the electron cloud. This is because Heisenberg’s uncertainty principle states that it is impossible to know both the position and momentum of an electron at the same time.
• The model allows calculation for all elements.

Conclusion:

The quantum model explains and solves all the defects of Bohr’s model.