Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers

# Electric Charge

Last updated: November 24, 2018

## What Does Electric Charge Mean?

This is a property of matter that is carried by particles and is expressed by the letter "e." There are two types of charges, namely, positive and negative. Every atom consists of a nucleus which contains protons and neutrons, and is surrounded by shells containing electrons. Charges either repel or attract—like charges repel while unlike charges attract.

A proton has a positive charge, an electron has a negative charge, while a neutron has no charge. When an atom has a positive charge, it means that the number of protons in the nucleus is higher than that of electrons around the nucleus. A negative charge means that the number of electrons is higher than that of the protons.

A charge is said to be quantized. This means that the charge is expressed as integer multiples of the charge e.

## Corrosionpedia Explains Electric Charge

Protons and electrons have equal sizes with different signs due to the amount of charge present. A proton, which is positively charged, has a sign of +e, while an electron has a sign of -e due to its negativity.

A quantized charge can be represented as:

q = n e

where

q is the symbol to represent charge

n is an integer

e is the electronic charge which is 1.60 × 10-19.

Both electrons and a protons have a charge of 1.602 × 10-19.

There are several states of an atom, depending with the amount of charge present:

• Ions: These are charged atoms with unequal numbers of protons and electrons.
• Uni-poles: These are particles which are electrically charged and can exist by themselves.
• Anti-matter: This can also be called a positron. These are particles that oppose a charge by creating an opposite charge.

Any charged particle develops an electric field around it. The charges dictate the direction of the field lines. A positively charged particle has field lines radiating away from the nucleus, while a negatively charged particle has field lines moving towards it. When two charges come together, the field lines either attract or repel each other. Although opposite charges attract, there are other forces like static electricity, colliding with anti-matter and not colliding with anti-matter that can affect the ions.