Structure of the Atom Definition, Types, Examples & Uses

Structure of the Atom

Subject: General Science

Book: NCERT Science Class 9

Atoms consist of subatomic particles: electrons, protons, and neutrons.
- **Atomic Models**:
- Dalton’s Atomic Theory.
- Thomson’s Model (Plum Pudding Model).
- Rutherford’s Model (Nucleus at the center).
- Bohr’s Model (Fixed energy levels).
- **Atomic Number and Mass Number**:
- Atomic Number = Number of protons.
- Mass Number = Number of protons + neutrons.

**Possible Exam Questions:**
1. Explain the postulates of Dalton’s atomic theory.
2. How does Rutherford’s model explain the structure of the atom?
3. What is the difference between atomic number and mass number?
4. Describe Bohr’s model of the atom.
5. Why was Thomson’s model rejected?