What are the limitations of J.J. Thomson’s model of the atom?

Explanation

**Step-by-Step Solution:**

1. **Introduction to J.J. Thomson's Model:**
- J.J. Thomson proposed the "plum pudding model" of the atom, which suggests that an atom is composed of a positively charged sphere with negatively charged electrons embedded within it. This model was likened to a watermelon, where the red part represents the positive charge and the seeds represent the negative charges.

2. **Limitations of the Model:**
- **Lack of Nucleus Concept:**
- One of the major limitations of Thomson's model is that it does not account for the existence of a nucleus. In reality, positively charged protons are concentrated in a small, dense nucleus at the center of the atom, which Thomson's model fails to explain.
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