The light emitted from the sun takes roughly 8 minutes before it reaches Earth.
If you take a basketball, and make it represent the sun, you need to take a small pebble and walk 3 city blocks before you have a comparable distance ratio.
An atom is composed rather like our solar system, but the orbits of the electrons is spherical, not eliptical... that is, where our solar system is relatively flat, the atom is more of a ball.
Take that same basketball to represent the nucleus of an atom. Taking that same pebble, now move it roughly 8 miles away, and that is roughly the distance that the closest electrons "orbit" around the nucleus in that atom. Between the nucleus and that first shell there is absolutely nothing.
An atom is so small, that you can't see it with the naked eye... nor can you see it with a standard microscope.
The nucleus, composed of protons and neutrons, make up the mass of the atom.
The protons have a value of one positive energy unit, while the electron has a value of one negative energy unit.
In an electrically neutral atom, there are an equal number of electrons and protons.
A proton and a neutron each have approximately one atomic mass. An atom with 10 protons and 13 neutrons would, therefore, have an atomic mass of 23.
The number of protons does not have to equal the number of neutrons, and in most cases, there are usually more neutrons than protons.
The number of protons in any given atom define what type of element that particular atom is. A gold atom has 79 protons, and lead has 82. Theoretically, if you remove three protons from lead, you have gold. Unfortunately, the process to do that takes more energy than it is worth. The process is called fission, or the blowing apart of atoms. Ever heard of the atomic bomb? That's what that does. And you have no guarantee that you'd get gold, because you would blow the lead atoms into just about every other smaller atom there is. Plus, you'd kill a lot of people and have all sorts of governments all over the world declaring war on you.
Then you have fusion, or the combining of atoms into heavier elements. But don't think about taking two smaller atoms and combing them to make your gold atom, either. Fusion takes a lot more energy than does fission. In essence, a bigger boom. Ever heard of the nuclear bomb?
Removing electrons is a lot easier, and far less destructive to the environment. That doesn't mean it's not destructive... after all, if you're exposed to enough x-ray radiation, things start to happen to you that can't be reversed. X-ray radiation is called ionizing radiation because it strips electrons from an atom. When that happens, the atom has a positive electric charge due to the loss of its equalizing negatively charged electron. Both the atom and the free electron are called ions, or free radicals.
In many instances, another free roaming electron may bind itself to the atom before anything happens. But, somtimes, especially if that atom is a part of some special molecule, the ionization of that atom will break apart the molecule. If it happens to be a molecule in your DNA, then you may suffer a mutation. Granted, it may be just in one cell of your body, and it may also be a particular DNA sequence that the cell is not utilizing... but one never knows. If it happens enough, though, you will start noticing it eventually.
It is still uncertain exactly what function the neutron serves. It is known that with radioactive matter where atoms release protons and electrons of its own accord, that neutrons will convert to protons. That's an interesting twist, isn't it! But protons can't convert to neutrons. At least, not that we know about.
Perhaps a neutron is responsible for gravity. After all, the mass of an object is directly equal to its gravitational pull. And atoms do have mass, granted, very very small. Eistein's theory of relativity, which deals with gravity, does not work at the atomic level. Those electrons are not bound to the nucleus of the atom by gravity, but by electrical charge. But, if you put enough atoms together, say to make a decent size planet, like Earth for example, you have one massive object that has gravity enough to keep us sitting in our chairs. But this is merely speculation.
But, gravity is a very weak force, compared to the nuclear forces that take place within the atom. At that level, gravity cannot be measured, and even if it could, it would make no difference. But, by the same token, the forces that run the affairs of an atom do not work on a grander scale, like that of the sun. Yes, there is still electromagnetic radiation and the like... but if the forces were as strong on such a scale as compared to that of an atom, well, it's very difficult to imagine how things could be different.
An electron travels at almost the speed of light when its zipping in orbit around its nucleus.
When travelling through conductive wire, an electron may move only about a millimeter per second. With Alternating Current (AC), it keeps moving back and forth, staying roughly in the same area. Sure, the energy running through that wire is travelling at the speed of light, but the electrons don't.
Okay, I'm just writing randomly. And I'm tired now, without a way to properly conclude this thing.