Atoms, the smallest particles of matter that retain the properties of the matter, are made of protons, electrons, and neutrons.
Atoms
Protons have a positive charge, Electrons have a negative charge that cancels the proton's positive charge.
Protons
Neutrons are particles that are similar to a proton but have a neutral charge.
Neutral
There are no differences between positive and negative charges except that particles with the same charge repel each other and particles with opposite charges attract each other.
No differences
If a solitary positive proton and negative electron are placed near each other they will come together to form a hydrogen atom.
Positive proton
This repulsion and attraction (force between stationary charged particles) is known as the Electrostatic Force and extends theoretically to infinity, but is diluted as the distance between particles increases.
Force
When an atom has one or more missing electrons it is left with a positive charge, and when an atom has at least one extra electron it has a negative charge.
Missing
Having a positive or a negative charge makes an atom an ion.
Positive
Atoms only gain and lose protons and neutrons through fusion, fission, and radioactive decay.
Gains
Although atoms are made of many particles and objects are made of many atoms, they behave similarly to charged particles in terms of how they repel and attract.
Particles
In an atom the protons and neutrons combine to form a tightly bound nucleus.
Nucleus
This nucleus is surrounded by a vast cloud of electrons circling it at a distance but held near the protons by electromagnetic attraction (the electrostatic force discussed earlier).
Vast cloud
The cloud exists as a series of overlapping shells / bands in which the inner valence bands are filled with electrons and are tightly bound to the atom.
Shells
The outer conduction bands contain no electrons except those that have accelerated to the conduction bands by gaining energy.
Conduction
With enough energy an electron will escape an atom (compare with the escape velocity of a space rocket).
Energy
When an electron in the conduction band decelerates and falls to another conduction band or the valence band a photon is emitted.
