I'm Cathy Renaud, and I'm a science teacher at Greenhills School in Ann Arbor, Michigan. And I'm delighted to be here to talk to you a little bit about the periodic table. On the wall behind me is a huge periodic table I use when I'm teaching and it's a wonderful, wonderful tool that might intimidate a few people when you first look at it. But it's organizational and we use organization in our lives. We like to categorize and that's what this does. It categorizes the elements that we know into a useful tool. And on a daily basis, humans like to categorize and organize. And if you go to a grocery store or a hardware store, it's organized. When you walk in, you can find the dairy section or the bakery section, you can find the electrical, you can find the plumbing. That's what this periodic table does. It provides an organizational mechanism for scientists and some non-scientists. Overall, when you look at this, you might be overwhelmed by all the information, but if you separate it and you break it down, we have some colors associated with it. In this particular one, the black indicate they exist as solids, the red indicate they exist as gases in the natural form, the blue indicate that they exist as liquids. The ones that exist in this outline form are non-naturally occurring. They are made by humans and they're very short-lived. So, the overall organization that we see, we have metals, we have non-metals. The metals are over here on this side, the non-metals are on the far right and we have a section in between that are called semimetals or metalloids. Now, in the metal section, we have three key ones that I want to point out right now, copper, silver, and gold. They're our coinage metals and when we look at them, if you think of them, they're shining, they're malleable, meaning you can hammer them into sheets. They're ductile, you can pull them into wires. They conduct heat, they conduct electricity. They're very useful to us. So, that's the characteristics we associate with metals. On the opposite side, the non-metals have characteristics the metals... opposite characteristics of the metals. They are not shiny, they're not ductile, they're not malleable. They're brittle actually if you hammer them. They don't conduct heat and electricity. The semimetals or the metalloids in between, they're the ones that have some characteristics of both and provide some unusual opportunities for people in the world to use such as silicon, element number 14, which is a huge component within your cell phones and your computers. Now, the periodic table itself in its current form is very different from what developed over a very long period of time with many scientists contributing. The current version has several elements beyond what our original scientists were working on. Dmitri Mendeleev, in the 1800s, late 1800s, is given the majority of the credit for the organization of our current periodic table, and he was trying to find a way to organize what he understood about the elements. And what he did was something no other scientist at the time did. He predicted the existence of elements yet to be discovered and he left gaps in the periodic table. And he predicted their properties. He predicted how they would combine with other elements, some masses associated with them, and when those elements were discovered several years later, the information he proposed lined up with the elements and he was dead-on in terms of his proposed characteristics and properties. So, he is given the majority of credit for the current organization of the periodic table. Now, his organization was based on atomic mass and if you look at the numbers in these lower portions here that are written in red, that's the atomic mass. It's composed of the number of protons and the number of neutrons. The atomic number in the upper right-hand corner is the number of protons. That was a newer addition. Henry Moseley, in the early 1900s, was the one that came up with that information and eventually just determined that that was just the mass of the protons or the number of protons, I'm sorry. So, the number of protons is what we have now used to organize the elements within this periodic table. If you also notice, these are not whole numbers. We've got some decimal places in there. And if you've ever heard of isotopes, isotopes are an element with different forms, same number of protons but different number of neutrons. And the most common form is carbon 12. That's what the majority of our bodies consists of, but there's also carbon 13 and carbon 14. And if you've ever heard of carbon 14 dating, that is the element... the isotope of carbon that decays or breaks down over time and we can compare it to what is in the atmosphere, so it allows us to date certain items that are carbon based. Within the periodic table itself, we have this wealth of information that to my knowledge, nobody has memorized. It's not worth it. So, what you use it for is looking at how things might combine with one another and what may not work at all. I use it in my chemistry class, pharmacists will use it, doctors will use it, engineers will use it, but those are the obvious people but there are others that may use this as well. If you're an artist, if you paint, if you do pottery or if you're a jeweler, that would be a common thing that you may want to use as well because you can find out a lot about the materials that you use in your world. So, it's a tool, it's beautiful, and I hope that you find some beauty in this piece of information that will help you in your life. 3.1 Navigating Periodic Table.txt[2016-08-25, 2:32:16 PM].