The Periodic Table of Elements How to understand the layout of the P.Table and to know what elements are in the first place…

#1 What are “elements” anyway? You probably recognize the name of many elements on the Periodic Table. Oxygen, Calcium, Iron, Gold…they’re all on there. But why isn’t water on the Periodic Table? Or brass? Or cookie dough? Because… The 100+ elements on the periodic table are all pure substances made of just one kind of atom. Let’s see what that really means.

#2 Joe and Janet Joe’s got some water Janet’s got some gold They agree to give each other an ITSY little bit of what they’ve got

#3 Joe and Janet Share! Janet takes her gold and, using the smallest knife you can ever imagine, she cuts her gold bar in half. And then in half again. And again. Over and over and over until she’s left with a tiny little bit that she can’t cut in half any more. So she gives to Joe one single gold atom. It does exactly the same things as the huge gold bar she started with, but it’s just a whole lot smaller. Gold is an element. It’s made of one kind of atom, different from calcium or silver or helium.

#4 Joe’s turn! Joe’s happy with his gold atom. He wants to give Janet a water atom. So he uses the tiniest little spoon you can imagine, and scoops away half his water. Again and again and again. But he finally gets to a point where… He’s left with 3 atoms…one oxygen atom and two hydrogen atoms stuck to each other. (Now H 2 O makes sense)! Joe borrows Janet’s knife and chops into this itsy bitsy water drop. As he makes his final cut, the water drop falls apart and the 3 atoms drift away into the air. Joe is sad that he has nothing to give to Janet.

#5 So that means that Water… …isn’t an element. Sure, it’s a pure substance, but it’s made FROM elements, specifically hydrogen and oxygen. That’s why you can’t find “water” on the Periodic Table. It’s the same reason why you won’t find “yogurt” or “dirt” or “puppy” on there, either. So…gold is made up of just ONE kind of atom…gold atoms! ELEMENT! And water is made up of different kinds of atoms stuck together. NOT an element! So everything in the universe made of matter is either a chunk of element, or is made FROM several elements! Yeah!

#6 So what makes a Gold atom different from, say, a Platinum atom? This is a big deal in 8 th grade science…learning how the elements are made from different kinds of atoms. Here’s the quick & easy 6 th grade answer: You’ve seen pictures of atoms like this for years in science books and videos. The 100+ elements of the Periodic Table each have a different number of Protons (the yellow spheres in this model), which are just parts inside an atom. Next year, you’ll learn more about this.

#7 Elements… Aluminum foil is made entirely from element #13, Aluminum! But “steel” is made from a combination of iron and carbon. Steel isn’t an element.

#8 Let’s get this thing sorted… Back in the 1800s, scientists knew of about 50 or 60 elements. It was confusing trying to keep track of all of them, and how they were alike and different, so several scientists set about trying to organize the elements in a useful manner. This guy, a Russian named Dmitri Mendeleev, succeeded. He wrote down information about the known elements, then put them together in alike groups. He figured if he could arrange alike elements in columns, with the “lightest” ones at top and “heaviest” ones at bottom, he’d make a nice, nifty chart.

#9 Mendeleev’s P. Table His chart had a ton of holes in it where he predicted new elements would be discovered. He could predict a lot of things about the missing elements, because they would be alike the elements around them. Mendeleev arranged his periodic table by atomic mass, or how “heavy” the atoms of that element are. His P.T. has trends and patterns for both the columns up and down and rows left and right.

#10 Review Elements are pure substances made of just one kind of atom. Everything else is made FROM elements combining together. Dmitri Mendeleev arranged the elements into the Periodic Table. In the P. Table, elements in the same column are very similar (alike). Elements in the same rows also share certain properties.

#11 “Groups” of Elements We’re going to break down the Periodic Table into 3 big groups and color code it. That’s good news, because we could get a lot more technical and have 9 or 10 groups instead. Be sure to color LIGHTLY so that you can still read the information on your paper. LIGHTLY.

Your name! NonmetalsMetalloidsMetals

#13 What makes those 3 groups different? Metals, nonmetals and metalloids differ in their physical & chemical properties (observable characteristics). We’ll learn much more about that stuff a little later.

#14 One More Thing… “What’s up with those two rows at the bottom?” is an often-asked question. It’s just a way to get the Periodic Table to fit on a normal-sized piece of paper. The way it should REALLY look is like this:

#15 And that is… …until we see in a few days how metals, nonmetals, and metalloids are different.