#### Charge

The world around us, and each one of us, is full of positive and negative charges. Electric circuits rely on the flow of charge, as does the human nervous system.

The symbol for charge is q or Q.

The MKS unit of charge is the coulomb (C).

#### Five facts about charge

- There are two kinds of charge, positive and negative
- Like charges repel. Unlike charges attract.
- In general, positive charge comes from having more protons than electrons; negative charge comes from having more electrons than protons.
- Charge is conserved
- Charge is quantized, meaning that charge comes in integer multiples of the elementary charge e.

q = ne, where n is any integer

e = 1.602 x 10^{-19} C

Rank the electron, proton, and neutron based on their mass, from largest to smallest.

Particle | Charge | Mass |

Neutron | 0 | 1.674 x 10^{-27} kg |

Proton | +e | 1.672 x 10^{-27} kg |

Electron | -e | 9.11 x 10^{-31} kg |

Other elementary particles also carry charge.