Chapter 28, Problem 57A

To determine

To describe: The different atomic models and identify their strengths and weaknesses.

Explanation of Solution

Introduction:

The different atomic models are:

1. The Rutherford Model
2. The Bohr’s Model
3. The Quantum Model.

1. The Rutherford model: The Ruther model described the atomic model as a solar system with electros orbiting around a nucleus like planets revolving around the sun.

Strengths:

a. It stated that atom nucleus is surrounded by electrons and electrons revolve around the nucleus in fixed circular paths called orbits.

b. It stated that the size of a nucleus of an atom is very small.

Weaknesses:

a. The comparison of electrons and planets. Electrically charged particles in motion radiate energy. According to Rutherford’s model, the electron revolving around the nucleus should after losing energy, fall in spiral path and collapse.

b. The stability of the atom was not explained.

2. The Bohr’s Model: According to Bohr’s model, the electron revolved around the nucleus in quantized orbits.

Strengths:

a. Bohr’s most significant contribution was the quantization of orbits.

b. Bohr’s model explained the stability of an atom.

Weaknesses:

a. Wave nature of an electron was not explained by the model.

b. It violated Heisenberg’s Principle.

3. The Quantum Model: The quantum model is based on probability rather than certainty. It uses volumes of space where there is likely for an electron to be. It predicts the probability of an electron in a certain region.

Strength:

a. It overcame the violation of Heisenberg’s Principle in the Bohr’s model by using probability rather than certainty.

Weaknesses:

a. The quantum model is difficult to visualize.

Conclusion:

The Quantum model is the most precise and correct among all.