Mike Stewart, age 13, of Durand, Michigan for his question:
What is copper made of?
Copper is made of copper atoms which is not as silly as it sounds. For copper is one of the basic chemical elements, each of which is composed of atoms of the same sort. We can describe the copper atom in fine detail and explain why its structure makes the metal we call copper behave the way it does. We also know that its unique atoms are unlike the atoms of every other chemical element.
Most substances in our varied world are built from molecules ¬and molecules are packages of assorted atoms. In the world of substances, it is atoms that bring us down to the nitty gritty, so to speak. For they are the basic building blocks of all substances and in our world of nature there are fewer than 100 different atoms.
We call them the basic chemical elements and they are charted on the neat. Periodic Table of Elements. Each atomic element has its own slot, with terse notations on the exact structure of its basic atom. There we find copper, under the shorthand name CU, which is taken from its older name. It is charted with a so called family of five other somewhat related metallic elements.
An atom is an orderly unit of particles, most of them charged with positive or negative electricity. Its core is the tiny nucleus, jam¬packed with positive protons, neutral neutrons plus a wide range of lesser particles. Normally it is surrounded by a number of electrons equal to the number of its protons.
Electrons may come and go, but the protons locked in the tight¬fisted nucleus cannot. If a proton is lost or gained, the atom becomes an atom of something else. Hence, the atomic number of each element is the number of protons in the nucleus of its atom.
The slot on the Periodic Table gives the atomic number for copper as 29. Since each element has one more proton than the next, this is always a whole number. It also tells us a lot about the electrons that swarm around the nucleus. In a normal copper atom there are 29 of them, to match the number of protons.
As in all atoms, the electrons are arranged in neat shells and their number tells us something about the element's behavior. The inner electron shell, closest to the nucleus, is complete with two electrons. The second shell is complete with eight and the third with eighteen. The normal copper atom has three complete shells, plus one left over to start a fourth shell. This lone electron is prone to leave home.
Electricity is a current of moving electrons and our electric wiring is made of copper. Voltage from a generator provides a jolt that frees zillions of lone electrons from the fourth shells of the copper atoms. They hop from atom to atom and their runaway energy is elect¬ricity.
Pure copper is made of nothing but copper atoms, which are all alike. As an element, it is classed with five others in the family of Third Transition Metals. The others are silver and gold, zinc and cadmium and mercury. Elements in this family have either three, four or five completed electron shells plus either one or two electrons in an outside shell.