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