 Let's start the day off with this question. Give the number of valence electrons for the following elements and draw their Lewis dot structures. Okay, so essentially the periodic table is your cheat sheet for this one. Just look up at the periodic table and I'll tell you how many valence electrons you got. So remember the group number tells you how many valence electrons you have. So hydrogen is in group one, so it's got one valence electron, so we'll put valence electron. Selenium is in group 16, so count. One, two, three, four, five, six, right? So six valence electrons. Am is in group two, all the way down. Do you see it? One of the bigger atoms in group two. So it's got how many two valence electrons, right? Arsenic is in group 15, right? So way over here in the P block. So count them up. So one, two, three, four, five valence electrons, right? Okay, so hopefully you can see the trend now that we're doing these types of things over and over and over. So iodine is in the halogens, our group 17. So how many do they have? Seven, right? And we're skipping over those transition metal D block electrons. Why? Because they're kind of, once you fill them up, they're inner electrons. And the neon gases, neon is one of the noble gases, so it's got a full octet of eight electrons. Okay, so let's go ahead and draw the Lewis dot symbols of these. So all you got to do is know the number of valence electrons these elements have and then go about just putting dots around each of the sides of the elemental symbols. So hydrogen's got one valence electron, so you start there with a one dot, okay? Selenium, six, so you just go around. One, two, four. Okay, so it's got two valence electrons or two orbitals that are unfilled. So it can make two bonds. That's actually what we're going to get out. Barium has got two valence electrons, so one. You may see these written like this. It's fine if you write it either way. I just think it helps to be standardized. Arsenic's got five, so start here. One, two, three. What you'll see is, since it's got three spaces where you can fit electrons, when it makes a molecule it'll be able to add three electrons to it. Some of these bigger atoms like arsenic, iodine can actually add four electrons. They'll expand their valence due to their d-electrons, but we'll talk about that, the d-orbitals. We'll talk about that later. Iodine is a valence electron. Is a halogen? It needs only one valence electron. Remember to become the noble gas configuration. So it'll have a total of seven. Oops, I'm not doing convention. Three, four, five, six, seven. So if we add that one, then it'll be I-minus. So this is just another way to represent the electron configuration, like the condensed electron configuration essentially. And neon's got its full octet, so one, two, three, four, six, seven. That's a pretty good survey of the different groups on the periodic table. Hopefully you can do these elements now after this day.