Who proposed the first model of atom?

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks who proposed the first model of the atom.

2. **Recall Historical Context**: The study of atomic structure began in the late 19th century. Various scientists contributed to the understanding of the atom.

3. **Identify the Scientist**: The first model of the atom was proposed by Sir J.J. Thomson in 1897.

4. **Understand Thomson's Model**: J.J. Thomson's model is often referred to as the "plum pudding model." In this model, he compared the atom to a watermelon. The seeds of the watermelon represent electrons, while the red part of the watermelon represents the positive charge of the atom.

5. **Clarify Limitations**: It is important to note that Thomson's model did not include the concept of protons or a nucleus, which were discovered later.

6. **Conclude the Answer**: Therefore, the answer to the question is that J.J. Thomson proposed the first model of the atom.

**Final Answer**: The first model of the atom was proposed by Sir J.J. Thomson.

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