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Atoms in Love
- University Press of New England
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103 same family, must also be unstable. Helium is highly stable and will not combine with any other elements (that is, there is no such thing as helium chloride); therefore the other elements in its group—argon, krypton, and xenon—will also not combine. (These elements are what are known as the inert or noble gases: they’re snobs who want nothing to do with other elements.) When I finish my three-lecture section on chemistry, I always feel that I am saying goodbye to a friend. Maybe this is because chemistry is so wrapped up in my nostalgia for the experiments I survived when I was a kid. But I also don’t like taking leave of Mendeleev, who became a real superhero in his time (except to the tsarist government, which didn’t approve of his republican leanings) and embodied the highest standards of science in his belief that through patient, focused probing of the data, answers will inevitably reveal themselves. In addition to sodium’s pyrotechnic lesson, I hope my students carry this one home as well. o p p p p p p p p p p p p p p p p p atomsinlove The non-science-majors’ fear of science is legendary. When cornered into taking a science course, they invariably select biology , the “non-math” science. In my experience, rarely does anyone elect to take chemistry for the fun of it. And with good reason. Chemistry is perceived as complicated, abstract, and quantitative. The triple whammy. In my introductory biology course I cover chemistry for a little over a week. I have to. Many biological processes cannot be understood without at least a passing familiarity with the 104 p i , t e a c h e r molecules that make them go. How can one talk about digestion without mentioning enzymes without mentioning enzymatic structure without mentioning how enzymes function? Actually, there are practitioners of the art of science teaching who say that this is indeed possible, through the development of courses with condescending names like “Biology for Poets.” This is not far removed from “Biology for Idiots,” which should be the purview of the mass-market paperback industry and not the universities. Be that as it may, and despite my bravado and calls for purism, I often find myself succumbing to the allure of creative imagery, romantic notions, and fantastic story lines to clarify concepts that my students struggle with. Take atoms, for example. These particles form the smallest part of any element. You can have an atom of gold, oxygen, boron, einsteinium, or any other element, but not less than this. If two or more atoms bump into one another they may combine to form a molecule. For example, H2O is a molecule consisting of two atoms of hydrogen and one atom of oxygen. The question is, how does this happen? And there lies the rub. In order to understand how atoms combine, or bond, we have to look inside them. All atoms consist of smaller units called subatomic particles , of which there are three types: protons, neutrons, and electrons . Atoms work the way they do because they are electrically charged. Protons are positive (think “P for positive”), neutrons neutral (“N for neutral”), and electrons negative (because that’s the only charge that’s left). Protons and neutrons are nestled together in the central core of the atom, the nucleus. Electrons, for their part, revolve around the nucleus. Picture the solar system: the sun (nucleus) is orbited by planets (electrons). So far so good (right?). Now, when atoms bond, you can forget about the protons and neutrons. The only thing that matters are the electrons. The question being begged is, how does one know how many electrons an atom has? This is what the Periodic Table of the Elements is for. It’s a reference that tells us precisely how many subatomic particles are in the atom of any [3.85.63.190] Project MUSE (2024-03-19 14:42 GMT) Atoms in Love p 105 element. Check out oxygen, symbol O. If you look at the periodic table, oxygen has two numbers associated with it. The smaller number tells us the number of electrons (actually, it tells us the number of protons, but the number of negative charges always equals the number of positive ones, for the sake of balance). In the case of oxygen, this number is eight. My students accept and understand this, and at this point in...