 All right. Hello everyone. Welcome to tutor terrific in this video. This is part two of our chemistry electron configuration and orbital notation series We're gonna go over orbital notation in this video And this is a good continuation of the electron configuration discussion in our last video so an orbital is Really an address for a pair of electrons, okay, and it's symbolized with a line I know it seems like they're supposed to be set in here But this is the symbol for the orbital itself two electrons can fit in each orbital One with spin up and one with spin down and we actually notate them like this With arrows the spin up arrow is always listed first and the spin down arrow is always listed last now Each sub level has a different number of orbitals. There are four different types of sub levels s p D and f the s sub level has one orbital two electrons in that orbital makes for two total electrons in each s sub level The p sub level has three orbitals So if we multiply that by the number of electrons in each we get six electrons in the p sub level The d sub level has five orbitals, which will make for 10 electrons and the f sub level has seven orbitals Which will make for 14 electrons So over here. I have the chart of The filling order that we used in our last video We start by filling 1s and then we go through this pattern At first everything's normal 1s 2s 2p 3s 3p and then we skip 3d go to 4s And then everything gets a little wonky so it's really good to have this filling order in front of you Now the way the orbitals are listed in orbital notation is like so We do not use the little letters here However, we do put the lines like so the little orbital lines The s sub level gets one line by itself spaced out from the next set Whatever it happens to be in the filling order. We always fill an s sub level if there's two electrons to fill it one up first then one down The p sub level will put the three orbitals next to each other like this with a small space between them in a Larger space between any other sub level around it. Here's how the p sub level must be filled First an up arrow then not a down arrow we go to the next spin up arrow And the next spin up arrow. That's if we have three If we have four we go back to the first Orbital and fill our first spin down electron If we have five we fill our next spin down electron if we have all six We fill our last spin down electron spot in the third orbital that filling order must be preserved D sub level got five orbitals small space between larger space between other sub levels around it We will do the same thing we did for p by filling all the spin up electron locations first Remember electrons don't like to be right next to each other quote-a-quote next to each other Because of their like charge like charges repel then we'll go back and we'll shove in the spin down electrons like so in That order then we have the f sub level Seven orbitals we will do the exact same thing for we did for P and D all the spin up electrons fill first Then we go back to the first orbital and we start filling The downward one so if we have 11 electrons, this is what it would look like 12 13 and 14 we must preserve this filling order for each of these sub levels always fill the spin up Electrons first and then spin the fill the spin down electrons. So I'm going to show you a few Elements now and their electro configurations, so we're going to create the orbital notation next to them Okay, here are the four examples for which we are going to make orbital notations. Let's start with the simple one carbon Carbon has six electrons according to its atomic number. Here is its electron configuration As you can see it's got a 1s a 2s and a 2p sub level so that means we're going to have our 1s orbital Space 2s orbital space and the 2p orbitals all three Notice how they are not full, but I must still write all the orbitals down Now let's start filling the electrons. Here is 1s And I will put the first two electrons in it up first then down. I'll even label them this time Here is 2s Both of those are filled up one first spin down one second and then the 2p I am going to start by filling Spin up electrons until I ran out of electrons to put in This is the orbital notation for carbon notice There's a whole empty orbital and that's just fine. Okay next we have argon We've got many more sub levels here because we have 18 total electrons So here's the 1s sub level the 2s sub level the 2p sub level The 3s sub level and the 3p sub level So we're going to fill up first then down in each s Notice how I don't skip to the next s until the previous s is filled then I will fill 2p 6 Ups first then the downs then I will fill 3s Then I will fill 3p 6 all filled up This is argon completely done completely filled That's because it's a noble gas an inert gas that doesn't like to react with anything because it has its valence electrons Which are the outermost s and p Sub levels in the outermost principle energy level those are filled. We have our octet Next chromium now I'm gonna have to start writing really small because now we have 24 electrons Notice how chromium is one of those transition metals that the d sub level takes one of the electrons from the Higher level s sub level because it's more stable Okay, I'm gonna speed through this first part and when we get to the interesting stuff. I'm gonna slow the video down Okay For s1, I do not fill the second electron in there because it's been taken by Dd has five 3d has five one two three four Five I know that seems strange, but this is how chromium does it Notice how the d sub level is exactly half filled much more stable than if I put that Electron back over here spin down it turns out Next Neodynium and D. This is a famous magnetic substance that is I should say element That is quite strong if you ever get your hands on a neodynium magnet. You won't believe your eyes So there's 60 electrons in here and we go all the way into the 4f Sub level that's because it's in the f block neodynium and it's filling its 4f sub level So again, I'm gonna speed this up until we get to the interesting part and then we'll start talking about what happens down there Okay, guys, I'm gonna slow her down for a second. Let's make sure we have the right orbitals 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f Okay, I'm gonna start filling these and I'll pause it when we get to an interesting part We're at 6s now and as you can see it's 6s 2 So we're going to Fill that up and then we're gonna start with 4f. There are four in here four All right now for neodynium it would have to borrow more than two from 6s and In actuality the rare earth metals in the f block actually borrow from another sub level other than 6s They borrow from something in five to fill their 4f and you could see to half fill 4f would take three electrons And it doesn't really have three electrons from any s sub level So it to turns that this is more stable notice again Three orbitals in the f sub level are not filled and the other four electrons that are in here are separated So they're all spin up in the four orbitals that start that sub level and the last thing I want to go over in this video something that some of you in the previous video Most likely wanted to see and that is noble gas configuration. Otherwise known as abbreviated configuration The idea behind this is that you don't have to write the entire Electron configuration you can abbreviate it by going back if you have a particular element you're looking at for example chromium here By going back and seeing what the closest Noble gas is with a smaller atomic number for chromium the case is argon now argon's Entire electric configuration is a portion of chromium's up to three p6 And so what's often done is that this is abbreviated just as argon So we'd write the electric configuration for chromium like this argon for s1 3d5 Everyone who knows noble gas configuration knows that this stands for all of this Argon's exact electric configuration as you can see this is quite helpful when you're writing electric configurations with large atomic numbers All right guys. This has been this two-part series on electric configuration on orbital notation. I hope it helps you leave some comments for me Thanks for watching. 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