 Well, hello, I'm Stephen Nesheba, and I want to tell you a little bit about atomic structure basics and the connection to the periodic table So I have a kind of a busy slide here, but basically what we need to know is That each atom has a tiny nucleus where there it is We're almost all the mass of the atom is and that nucleus if you look at it closely is made up of things called protons Things cause neutrons and the protons have a positive charge and the neutrons don't have any charge at all The rest of the mass is what we call this cloud of lightweight fast moving electrons and Each electron has the opposite charge to an to a protons. We would say it has a minus one charge The Ongström or Ongström is a good distance unit for that cloud or the atom Turns out the smallest atoms measure about two Ongstroms across and the biggest which is Cransium is a little bit more than four Ongstroms across so Ongström is kind of a useful unit Also, the electron clouds are layered kind of in a sense and the layers are called shells so each layer gets bigger and bigger and We call those shells and I've just kind of shown a picture of that. So here's a here's some of the smallest atoms There's a hydrogen only has one proton and it's nucleus. Here's a helium has two There's just one shell of electrons around Those two atoms here. We have eight atoms that have two shells here We have eight more atoms that have three shells and to organize things that the ones with the first one shell It's called period one period two. They have two shells period three has three shells and then in the vertical They're kind of organized by groups And so on in this last group you They all have names actually this one is called the The inert gases or the noble gases. These are the halogens way back over here. There's there's the there's the alkaline metals So Now to get to the periodic table There's there's the structure of this periodic table is this on kind of the left way over here Those are called Metals, okay, some of you might recognize there is iron and copper and And silver a lot of metals are really stable Some of them are explosive like lithium and sodium way over here if you if you expose them to water And in fact if you count up all the elements most you can see most elements are actually metals Now on the right or what we call non metals. That's these guys over here. I'm leaving out the purple ones here Most of them combine with each other to form what we call covalent molecules some of which you recognize That's the oxygen that we need to breathe. That's nitrogen So you're to those are all in air and I mentioned before the noble gases That's what is in this last column on the right. They they don't usually bond very much Now another thing. Alright, so we've got metals over here non metals over here Now it turns out that when a metal combines with the non metal The result is what we call a salt and you're quite familiar with sodium chloride. That's table salt And if we can find it here, there's sodium definitely a metal and here's chlorine Definitely a non metal. So when metal combines with non metal, we get salt, sodium chloride and Let's see So the the last bit of this I just want to make the connection between them So here's that periodic table that I just saw and here's that bunch of Diagram of shells So you can see the first period of the periodic table. Those are the ones hydrogen helium There's only one shell the second period of the periodic table lithium beryllium Here you see lithium beryllium all the way off to neon They have two shells and the third has three shells and After that it gets a bit more complicated But that's really really the big connection between atomic structure in the periodic table That's that's really useful to keep in mind