The atom, besides being the building block of the universe, is important to understand for an effective study of electricity. While the atom is very complex and one could spend a lifetime studying it we will concentrate on what is important to the study of electricity
This is the simplest atom, Hydrogen, consisting of one proton making up the nucleus
and one electron in orbit around the nucleus. The other particle in an atom's
nucleus is the neutron (there is no neutron in a hydrogen atom). For the purpose of
studying electricity it is sufficient to know that atoms exist and that electrons
circle around them.
Some atoms have lots of electrons.
Electrons are negatively charged and Protons are
positively charged. Neutrons have no charge.
The orbit in which the
electron travels around the nucleus is called it's
valence shell. The more electrons in an atom the more valence shells are used.
Only the outer valence shell is important to us. When there is only one electron in the
outer valence shell it is very easy to free it from it's
atom. This can be done by heat or the application of
electricity. The traveling of electrons from atom to atom is
electricity. These traveling electrons are called free
electrons.
Normally atoms are
neutral. That is to say that they have the same number of
Protons as Electrons. When the electron leaves it's atom
the atom becomes positively charged. The electron that has
left joins another atom giving it a negative charge. It is
important in the study of electricity to remember how charges
behave. Alike charges repel each other while opposite
charges attract.
Some atoms make good conductors. This is due to the number of electrons in their outer valence shell. Some good conductors are copper, gold, silver, tungsten. Some atoms make good insulators. This is also due to the number of electrons in their outer valence shell. If an atom has just the right number of electrons to fill it's outer valence shell it resists giving up it's electrons to the freedom of becoming electricity.
Click here for Quiz 1
