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Biomolecules and the Chemistry of Life
Biomolecules and the Chemistry of Life

Protons, Neutrons, and Electrons

Chemistry 101 – A Subatomic Soap Opera

When it comes right down to it, the atomic world has enough drama to rival the most epic telenovela. There’s love. There’s hate. Bonds are formed and broken. And yes, there’s scandal. First things first…

The Main Characters

The proton is a glass-half-full kind of gal: she has a positive charge, gets to be in the atomic nucleus—who doesn’t like being the center of attention?—and gets to hang out with her BFF, the neutron. The neutron is totally fine with this association because she gets to live in the nucleus free of charge. Get it? A single proton weighs 1.672623 × 10-24 g, and a single neutron weighs just a little more, at 1.6749286 × 10-24 g.1

Together, protons and neutrons constitute most of the mass of the atom. Skulking around the periphery are the electrons. They have a negative charge and are much lighter and smaller than the proton and neutron, weighing only 9.109389 × 10-28 g1. Their "lives" literally revolve around someone else, and their minuscule size and mass make them feel invisible. No wonder they are so negative. OK, maybe we’re projecting. For better or worse, though, these protons, neutrons, and electrons together comprise the atom. In a regular old atom, there is exactly the same number of protons as there are electrons. This means that the unit as a whole is electrically neutral: their positive and negative vibes cancel out.

In nature, there are 92 kinds of atoms. The only thing that makes one kind of atom different from another kind is the number of protons present in the nucleus, or the atomic number. Each kind of atom is the fundamental structural unit of a different element.

Elements are substances that cannot be broken down any further without losing the most honorable distinction of "substance." All elements are listed for your viewing pleasure in the periodic table of elements. For example, an atom of the element oxygen, O, which has an atomic number of 8 (or 8 protons), is the smallest "piece" of oxygen that you can ever have. If you break it down more than that, you have subatomic particles, but they will not have the properties of oxygen. It would be like eating a mouthful of flour (yuck) when what you really want is a chocolate chip cookie.

Presenting, carbon (12C): 



And his two-doors-down friendly neighbor on the periodic table, oxygen (16O): 



By the way, that superscript number next to the element is equal to the total number of protons and neutrons in the element. Doing a quick little calculation, we know that carbon-12, or 12C, has 6 protons and therefore, 12 – 6 = 6 neutrons. Oxygen-16, or 16O, has 8 protons and 8 neutrons.

Brain Snack

Some bacteria actually make little, tiny electrical wires down which electrons flow. They are called nanowires and you can check them out here.
Next Page: Isotopes
Previous Page: Intro

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