The atom is the smallest unit of matter that retains the properties of an element. It consists of two distinct regions.
Subatomic Particles
| Particle | Rel. Mass | Rel. Charge |
|---|---|---|
| Proton | 1 | +1 |
| Neutron | 1 | 0 |
| Electron | 5 × 10⁻⁴ | −1 |
Deflection in Electric Fields
Charged particles moving through an electric field are deflected. The amount of deflection depends on Charge (z) and Mass (m).
Deflection \( \propto \frac{\text{charge}}{\text{mass}} \)
- Electrons: Huge deflection towards Positive plate (very light).
- Protons: Small deflection towards Negative plate (heavy).
- Neutrons: No deflection (neutral).
Proton
Neutron
Electron
Li
7
3
A (Mass No) = p + n = 7
Z (Atomic No) = p = 3
Neutrons = A − Z = 4
Electrons = p = 3