The nucleus, an atom’s powerhouse

Al Lowe
Contributor

The Nucleus: The Atom’s Powerhouse
So far we have seen that the atom is the smallest part of an element, and that it is like an infinitely small solar system. The positive nucleus is at the center, and the negative electrons whirl around the outside.
The electrons are very important to us. These are the things which, in uncountable billions, rush through wires to give us electric light and heat. But the heart of the atom is the nucleus. It is when we are able to control the nuclei of atoms that we get really immense amounts of energy. If this huge amount of energy is released quickly, then we get an explosion, as in a nuclear bomb. But if it is released slowly, and in a controlled manner, that energy can run an electrical generator, as in a nuclear power plant.
Remember that the nucleus is composed of two major parts - the positive proton and the neutral neutron. (There are many other little particles in there, but we don’t need to worry about them). The proton is the thing which plays the key role in the atom - it determines just what the atom is.
Use your imagination again. Imagine that we could examine a single particle of Oxygen. This is a familiar substance, part of the air which you breathe. It keeps you alive! Now this Oxygen atom has eight protons in its nucleus - never any more or any less. It may have some neutrons in there too, seven or eight, perhaps , but it must always have those eight protons. In our imagination, let us knock out one of those protons. Obviously, we have seven left. But the catch is, we no longer have an atom of Oxygen. Instead, we have an atom of Nitrogen - a different gas. This gas makes up about four fifths of the air we breath. Any atom which has seven protons in its nucleus is Nitrogen.
Use your imagination again, and knock out another proton. Now there are six. But the atom isn’t
Nitrogen any more, but Carbon. Carbon has just exactly six protons, always.
And so it goes, up and down through the 100 or so elements which make up our universe. Protons determine what the element is. The number of neutrons can change, and so can the number of electrons, without changing the characteristics of the atom very much.
Normally, it is quite difficult to change the number of protons, in an atom. But some of the heavy elements do it all by themselves. Atoms like Uranium, Radium, Plutonium, Radon and others, are just naturally radioactive, as we call it. Their nuclei break up from time to time, and little parts fly off. Sometimes the part which flies off is positive, sometimes neutral, and sometimes negative. When a part flies off, the atom is changed in some way. We shall take a look at that later on. Even a few atoms of common substances are radioactive. Carbon, for example. Right now, you have a few atoms of radioactive Carbon in your body, and Oxygen, and Calcium, and others. And you didn’t even know it!
The diagram shows the basic structure of one of the simplest of all atoms. As more proton, neutrons and electrons are added, the picture becomes much more complex indeed!