 Okay, so let's go ahead and do this problem. It says, and this is in fact the way I want you guys to present to me your problems. So you can just go ahead and photocopy it or PDF it and send it to me an email and we'll just do it. But so Adam sent me this problem that says, complete the following table by providing the symbol or formula that is used to represent a sample of the element under normal conditions. So that means like 25 degrees Celsius atmospheric pressure and temperature. Okay, so our atmospheric pressure and temperature. So the first one is iodine. Okay, so the answer is wrong that you put, right? You put I and the answer in actuality is I2. Okay, so why is it I2? That's the question. Well, if we look at iodine and we look at the number of valence electrons it has. Okay, so iodine, I know we just learned about valence electrons today, but when we're talking about octets we skip over what we call the transition metals here. Okay, so iodine just like any of the other halogens have one, two, three, four, five, six, seven electrons in its valence shell. Okay, does that make sense? Has seven of the electrons? So the way we would represent that is like this. Remember electrons are in pairs. If they're not paired up, they're not stable. Okay, so notice there's one unpaired electron in this molecule. Okay, does that make sense? Do you see that? Okay, so this is another way to draw it, not the planetary, but instead of the nucleus we stick the actual chemical symbol and only draw the valence electrons, because the valence electrons are the only ones that are reactive. Okay, so that's iodine. So does it have a complete valence shell? No, so it needs to complete its valence shell to be stable. So right now it's super reactive. Okay, so if it comes into contact with another iodine atom, okay, don't worry about it. We've got to finish talking about it, okay? So what will happen is, remember, electrons like to be paired, okay? So what will happen, and these are called curved arrows, we'll talk about this in a little bit, is, so you want to do a fish hook arrow, so notice it looks like a little fish hook, right? Why does it only have half a head? Because it's showing only the motion of one electron, okay? So an arrow that's like this, that's the motion of one electron, okay? So that and like that, right? So now we get something that looks like this, like that. Notice the unpaired electron from this iodine and the unpaired electron from this iodine are now paired in between the two iodine atoms. Do you see that? Okay, that pairing of electrons, we will simplify now and we write it as what we call a covalent bond to actually show the fusion or the joining of those two iodine atoms. So any shared pair of electrons between two atoms are now represented by a covalent bond. Shared pair electrons. Does that make sense? So the next one is neon. Neon has what? If we look at neon, talk about its octet for me. Neon is NE, so it has a full octet. So it's a noble gas, right? So does it like to react with other things? No, it won't react with anything. So it won't be a molecule. It will stay as an atom, okay? Yeah, that's it, that's it. Yeah, it's happy, right? Because why? Because let's draw these things over here. These are called Lewis structures when we put the symbol in the valence electrons around them. Let's draw the Lewis structure of neon. It's a full set and they're all what? More importantly, they're all paired. Yeah, they're all paired, okay? So they're happy. Hydrogen, and let's see about that one. Let's just do this. What should hydrogen be? It should be H2, right? Why? Because we've got one electron there. One electron there. Yep, they like to be paired. So I'm going to skip that intermediate step and just draw like that. So it's going to be H2, right? And then all the rest are the same thing, you know? Same thing. So just keep going over those. The other things, one other thing I'd like to tell you is that there's a staircase here. This periodic table doesn't really show it, but you can see it in your periodic table. There's a staircase that goes like that, okay? Anything to the right of that staircase is a non-metal. Anything to the left is a metal. Anything that's a metal will always be by itself, okay? Okay, except hydrogen. Hydrogen does...it's a non-metal, okay? Okay? So hopefully that helps out. This is the stuff we're going to be going over on Wednesday or whatever.