Atoms and Charge Transfer

• There are four fundamental forces in nature.1. Gravitational2. Electromagnetic3. Strong Nuclear4. Weak Nuclear

• The force that holds atoms together is the strong nuclear force.

AtomsElectrons- orbit nucleusNegative charge of -1.6 x10-19C

Nucleus- Center of an atom

Neutrons- in nucleusNeutral (no charge)

Protons- in nucleusPositive charge of 1.6 x10-19C

• Charge (q or Q) measured in a unit called Coulombs (C).

• Charges of like signs repel.• Charges of opposite signs attract. • Neutral atoms have equal numbers of

protons and electrons. • Electrons are able to move from one place to

another, protons are not.

Charge TransferCharges can be transferred 3 ways

1. Conduction (Friction and Contact)2. Induction (nearness of charged objects)3. Polarization (temporary realignment)

1. Conductors- allow electrons to move freely, usually charge will sit on the surface.2. Insulators- charges are more tightly bound. Even charge distribution.3. Semiconductors- usually mixed with an alloy to turn an insulator into a conductor.4. Superconductors- very low resistance to the flow of charge at certain temps. Can conduct electricity without heating.