Electrons and Protons in the Atom

Although there are many number of posibble methods by which electrons and protons might be grouped, they assemble in specific combinations that result in a stable arrengement. Each stable combination of electrons and protons makes one particular type of atom. Figure 1 illustrates the electron and proton structure of one atom of the gas hydrogen. This atom consists of a central mass called the nucleus and 1 electron outside. The proton in nucleus makes it the massive and stable part of the atom because a proton is 1840 times heavier than electron.

In figure 1, the 1 electron in the hydrogen atom is shown in an orbital ring around the nucleus. In order to account for the electrical stability of atom, we can consider the electron as spinning around the nucleus, as planets revolve around the sun. Then the electrical force attracting the electrons in toward the nucleus is balanced by the mechanical force outward on the rotating electron. As a result, the electron stays in its orbit around the nucleus.

In an atom that has more electrons and protons than hydrogen, all the protons are in the nucleus, while all the electrons are in one or more outside rings. For example, the carbon atom illustrated figure 2a has 6 protons in two outside rings. The total number of electrons in the outside rings must equal the number of protons in the nucleus in a neutral atom.

The distribution of electrons in the orbital rings determines the atom’s electrical stability. Especially important is the number of electrons in the ring farthest from the nucleus. This outermost ring requires 8 electrons for stability, except when there is only one ring, which has a maximum of 2 electrons.

In the carbon atom in fig. 2a, with 6 electrons, there are just 2 electrons in the first ring because 2 is its maximum number. The remaining 4 electrons are in the second ring, which can have a maximum of 8 electrons.



As another example, the copper atom in Fig. 2b has only 1 electron in the last ring, which can include 8 electrons. Therefore, the outside ring of the copper atom is less stable than the outside ring of the carbon atom.

When there are many atoms close together in a copper wire, the outermost orbital electrons are not sure which atoms they belong to. They can migrate easily from ane atom to another at random. Such electrons that can move freely from one atom to the next are often called free electrons. This freedom accounts for the ability of copper to conduct electricity very easily. It is the movement of free electrons that provides electric current in a metal conductor.

The net effect in the wire itself without any applied voltage, however, is zero because of the random motion of the free electrons. When voltage is applied, it forces all the free electrons to move in the same direction to produce electron flow, which is an electric current.

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Negative and Positive Polarities

We see the effects of electricity in a battery, static charge, lightning, radio, television, and many other applications. What do they all have in common that is electrical in nature? The answer is basic particles of electric charge with opposite polarities. All the materials we know, including solids, liquids, and gases, contain two basic particles of electric charge; the electron and proton. An electron is the smallest amount of electric charge having the characteristic called negative polarity. The proton is a basic particle with positive polarity.

Actually, the negative and positive polarities indicate two opposite characteristic that seem to be fundamental in all physical applications. Just magnets have north and south poles. Electric charges have the opposite polarities labeled negative and positive. The opposing characteristics provide a method of balancing one against the other to explain different physical effects.

It is the arrangement of electrons and protons as basic particles of electricity that determines the electrical characteristic of all substances. As an example, the paper has electrons and protons in it. There is no evidence of electricity, though, because the number of electrons equals the number of protons. In that case the opposite electrical forces cancel, making the paper electrically neutral. The neutral condition means that opposing forces are exactly balanced, without any net effect either way.

When we want to use the electrical forces the associated with the negative and positive charges in all matter, work must be done to separate the electrons and protons. Changing the balance of forces produces evidence of electricity. A battery, for instance, can do electrical work because its chemical energy separates electric charges to produce an excess of protons at its positive terminal. With separate and opposite charges at the two terminals, electric energy can be supplied to a circuit connected to the battery.

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Electricity

Electricity is an invisible force that can produce heat, light, motion, and many other physical effects. The force is an attraction or repulsion between electric charges. More specifically, electricity can be explained in terms of electric charge, current, voltage, and resistance. The corresponding electrical units are the coulomb for measuring charge, the ampere for current, voltage for potential difference, and the ohm for resistance. A basic element of electricity is the electric circuit. A circuit is a closed path that allows for the movement of charges. Current is the name given to the movement of charges. The study of electricity involves the behavior of charges, current, and voltage with the components that make up the circuit.

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