Videos

Periodic Table: Periodic Trends of the PT

Added Nov 04, 2015 •

Copy this URL:
Embed code:	<iframe class="edlio-embed-player" type="text/html" width="640" height="360" src="//bhs.bartlettschools.org/apps/embed/?v=94210" frameborder="0" allowfullscreen></iframe> Change dimensions

Show Transcript

hi it's Paul Anderson in this is chemistry Essentials V is exits on periodicity in other words it's going to be the patterns that we see in the periodic table now what determines that is going to be electron configuration and we can figure that out using the stop brow principle which is actually German and it means the principle of building up so we're building up from lower to higher energy levels and so what we can find is trends that start to emerge but it's most important instead of just memorizing them that you really understand what's going on inside the atom determines those those what's up. Icity remember is going to be drive from the electron configuration in other words where the electrons are we can determine that by do it using the aufbau principle where to watch the last video on electron configuration I think that helped a lot but what's the meaning behind this it all comes from Coulomb's law which helps to explain electron configuration it also helps explain these trends that explains changes in the ionization energy changes in the atomic and ionic radii how big the atom or where is electronegativity and finally the ion charge and so if you really understand Coulomb's law you can kind of work your way through this on the periodic table why is this important we can use the play table to make predictions especially about things that we haven't even designed yet and so if we look at the periodic table this on the right side is going to show us which of these are going to fit sailed over time but if you look at the periodic table we'll find trans and so here's hydrogen what we really need to do is take helium and then put it over in this ass Block it's going to make us it's play easier to understand and so what we're going to have our energy shells and then these would be subshells within that it's a one thing you should understand about the periodic table is this A Flock should slide writing hear it be hard to write a convenient periodic table but that's really how it should be set up couldn't generally we've just put it down below so what's guiding this or explaining the electron configuration remember is Coulomb's law and so it's pretty simple if we look at the protons on the inside of the nucleus they have a positive charge the electrons have a negative charge and so Coulomb's law says we just multiply those and other words the bigger they are the bigger the force between the two is going to be but as we Chris the radius the distance between the nucleus and those electrons then we're going to see a decrease in that Force the one thing that you have to add to that is it once we fill up one of these orbitals or subshell it's going to Shield the electrons on the outside from those on the inside so let's get started and work through this list what's going to happen to the ionization energy let's look at Coulomb's law ionization energy is the energy required to pull one of these electrons away and so what's going to happen as we increase the size of atoms wear play increase the number of protons in so we're going to make it harder for you to pull an electron away and so we move across the periodic table we're going to see an increase in rain is Asian energy what's going to happen as we go down the periodic table well as we go down the periodic table they're getting bigger and bigger and bigger and so the radius is going a larger and so therefore we're going to see a decrease in ionization energy so you can think of a Novation energy going up into the right now it's not as simple as this what we're really looking at is within subshells were going to see that pattern because you'll see changes within here and orbitals as well but it's just a general Trend and it comes from Coulomb's law let's look at a Tomic ionic radii will what happens as we increase the atomic number were increasing the number of protons what is that going to do it's going to pull in another words that's going to pull those electrons more closely to the center Intuit actually going to be the opposite it was going to increase as we go down and it's going to increase as we go from the right to the left across the periodic Sable and so you can see this graph of atomic radii is actually going to be the inverse of what we saw with ionization energy what about electronegativity electronegativity is how much an electron and it's bad to say this but once an electron in other words how much it would like to receive another electrons will remember as we're going across subshell let's say we're going to classes p-block right here as we go across we're increasing the number of protons and therefore were increasing that pull of the nucleus on the electrons outside it and so as we move from the left to the right we're going to increase how much that Adam wants an electron at least until we get to the noble message until electronegativity is going to follow ionization energy as well what if we look at then ionic charge while to look at ionic charge we really so look at how close anatomies to a noble gas and Celeste throw noble gases up here noble gases are going to have a full inner electron and so anything that moves you towards that is going to make you more stable atom it's a remember the only atoms that exist by going to be the noble gases up here so quick way to figure out ionic charge using Coulomb's law it's a just look how close you are to a noble gas and so let's look at the halogens which are right here how many electrons would halogens have to get in order for them to move to a noble gas will just one electron and so they're going to have in general and negative one charge let's move over these it have negative to negative three let's go way to the other side with the alkali metals what about them well it would be hard to go all the way across here to get to noble gases just easier to go around the back and otherwise they could lose the electron and when you lose the electron you have a positive one charge and so we could kind of work it up in this direction as well then so again that's snot holdfast in other words these are General Trends but they can all be predicted just by applying coulombs locked so it's hard to talk about the periodic table without talking about de me Mendeleev who's really the father of the periodic table but you probably never heard of Julius Von Mayer was a German who was working on the periodic table at the same time and publish periodic table around the same time as Mendeleev now why haven't you heard of Meyer well Mendeleev made these huge predictions and other words here's his periodic table you see here that you had some? Where they hadn't identified those atoms would have did his he would predict them and so he predicted germanium and he called it Equis I'm in here all the predictions he made about the properties of this ekasilicon and if we look at his predictions and then compare it to the actual values all the way down you'll find he was pretty much spot-on and that's why Mendeleev is given credit for the periodic table Not only was he able to build it put it everybody also made these great predictions and his predictions were spot-on and so that kind of lens to this next topic I wanted to talk about which is material design what we can do is we can things off the periodic table so let me grab some Adams let me grab some silicon and some oxygen and so we make some silicon dioxide and when we do that we get Ceramica ceramic is going to be build up maybe stoneware or earthenware so it's going to be able to up these tiles over here on the side instead of silicon side can make that well what about something below that what about 10 if I were to grab that I could say maybe those are going to form Ceramics and they will though form glazes that are going to be on ceramic tiles as well as they can dance around the periodic table and if you know some of these Trends you can make predictions about new materials and so again in Siri. Icity comes from the electron configuration which is determined by the aufbau principle but what really explains it is Coulomb's law which allows us to make these big ionization remember goes up into the right atomic radii increases down into the left electronegativity up into the right and then ionic charge where where we find where the noble gases are and then we look at how many electrons we have to gain or lose to get there and then these are important in designing material so you should have learn to predict or just play TranZit Atomic properties where would I point you if you didn't get that remember looking at this chart and and seeing how I Novation and electronegativity change where to look at justify Arrangement based on on reactivity it all goes back to Coulomb's law and remember the bigger the charges are the bigger the ionization energy or the bigger the force holding the elect same place is going to be there's also the shielding effect and then remember we can identify patterns to predict design and the example of silicon and 10 oxides are example of that so that's. It's City and I hope that was helpful

Uploaded by Laura Houston.

Videos

Periodic Table: Periodic Trends of the PT

More videos from Laura Houston