Subatomic Particles
Q12: Write down the fundamental properties of the fundamental particles of an atom?
OR
Write fundamental properties of electron, proton and neutron?
OR
Elaborate the concept of subatomic particles by showing their mutual relationship?
Fundamental Particles of an Atom
Atoms have more than 100 sub-atomic particles, but three are most important: Electron, Proton, and Neutron. These are called fundamental particles.
1. Electron
- Negatively charged particle.
- Moves around the nucleus.
- Charge:
-1.6022 × 10⁻¹⁹C. - Mass:
9.11 × 10⁻³¹kg.
2. Proton
- Positively charged particle.
- Located in the nucleus.
- Charge:
+1.6022 × 10⁻¹⁹C. - Mass:
1.6726 × 10⁻²⁷kg (1837 times heavier than electron).
3. Neutron
- Neutral particle (no charge).
- Located in the nucleus.
- Mass:
1.6749 × 10⁻²⁷kg (1842 times heavier than electron).
Sub-Atomic Particles Comparison
| Particle | Charge | Mass (kg) |
|---|---|---|
| Electron | -1 | 9.11 × 10⁻³¹ |
| Proton | +1 | 1.6726 × 10⁻²⁷ |
| Neutron | 0 | 1.6749 × 10⁻²⁷ |
Q13: Illustrate the behavior of protons, neutrons, and electrons in an electric field?
Behavior of Protons, Neutrons, and Electrons in an Electric Field
1. Protons
Protons have a positive charge (+1). In an electric field, they move towards the negatively charged plate.
2. Neutrons
Neutrons have no charge (0). They are not affected by an electric field and remain stationary.
3. Electrons
Electrons have a negative charge (-1). They move towards the positively charged plate in an electric field.
Q14: Why atoms are neutral?
Why Are Atoms Neutral?
Atoms have no charge because they have the same number of protons and electrons. Protons have a positive charge, and electrons have a negative charge. Since they cancel each other out, the atom stays neutral.
Q15: What are Radioisotopes?
Radioisotopes
Radioisotopes are atoms of the same element. They have the same number of protons but a different number of neutrons. This makes them unstable. To become stable, they release radiation.
Characteristics
- Same number of protons
- Different number of neutrons
- Unstable nucleus
- Emits radiation (alpha, beta, gamma)
- Used in medicine, industry, and research
Examples
- Carbon-14: Used to date ancient objects.
- Iodine-131: Helps treat thyroid problems.
- Uranium-238: Powers nuclear plants.
isotopes, protium 1 1 H, deuterium 2 1 H or D, and 3 1 H, Tritium or T
3.2 Subatomic Particles
Main Subatomic Particles
1. Proton
- Relative charge: +1
- Relative mass: ~1 atomic mass unit (amu) or 1.6726 x 10-27 kg
2. Neutron
- Relative charge: 0 (neutral)
- Relative mass: ~1 atomic mass unit (amu) or 1.6749 x 10-27 kg
3. Electron
- Relative charge: -1
- Relative mass: ~1/1836 amu or 9.11 x 10-31 kg
Location and Interactions
- Protons and neutrons: Found in the nucleus
- Electrons: Orbit around the nucleus in energy levels or shells
- Nuclear force: Holds neutrons and protons together in the nucleus
- Exists between: neutron-neutron, proton-proton, and neutron-proton
Mass and Charge Relationships
- Protons and neutrons: Similar mass (~1 amu), significant contribution to total atomic mass
- Electrons: Much less mass, negligible contribution to total atomic mass
- Atom cohesion: Interaction between negatively charged electrons and positively charged protons
Behavior in Electric Fields
- Protons: Deflected towards negative plate
- Electrons: Deflected towards positive plate (more strongly than protons at same speed)
- Neutrons: No deflection, travel straight
Charge Neutrality
- Atoms are electrically neutral
- Number of protons = Number of electrons in a neutral atom
Radioisotopes
- Definition: Atoms with unstable combination of neutrons and protons or excess energy in nucleus
- Isotopes: Same number of protons, different number of neutrons
- Examples: hydrogen-3 (protium), carbon-14, uranium-238