Periodic Trend: Electron Affinity

here. We're saying that electron affinity abbreviated as E. A. Is the energy released making it exile thermic from the addition of an electron toe, a gaseous atom or ion in killing jewels. Now, you may also get it in kilograms per mole, but for the most part, we're gonna say it's in Justin Kelly jewels. Now we're going to stay here. We're talking about adding an electron to an atom or ion. So here we have neutral carbon. We're gonna add an electron to it. So here is the electron we're adding. When it gains that electron, it becomes mawr Negative. So now it's going to be C minus as a gas. Now here this is an extra thermic reaction. So in an exotic reaction, we release energy in order to create a bond. Releasing energy means that we're gonna have a negative sign for electron affinity. Now we're going to say here that the mawr negative the electron affinity value is in the mawr eggs, a thermic the reaction becomes, and we're gonna say here that there are exceptions when we look at the periodic table in the next video. There are exceptions to electron affinity for the exceptions were going to say that they are equal to or greater than zero. And that means the element will not readily accept an electron. So if you're electron, affinity is zero or higher. That means that element does not want to accept, or it cannot accommodate a new electron because it interrupts their stability. So now that we've talked about electron affinity, click on to the next video. We'll let's take a look at the periodic table.

So if we look at the periodic table, we see that for electron affinity. We're going to say that it becomes more eggs a thermic so we could say that it increases as we move to the top right corner, the periodic table. So notice here we have negative 72.8 for hydrogen, and we have negative 3 28 for flooring. Remember, the more negative your electron affinity, the more excell thermic reaction that means it wants the electron, even Mawr, so we can see that flooring wants an electron even more than hydrogen. If we go down, we can see here that caesium is negative 45.5, so it doesn't as readily want an electron. Also, notice here that the bottom row does not have any values. Those elements are so large, so unstable that we tend not to talk about their electron affinity. You'll also notice that certain elements are have electron affinities that are equal to or greater than zero. So we have beryllium here we have nitrogen. We have the noble gas, which makes sense because they're perfect, so they don't require accepting an electron. They don't need it. Some others are not as commonly seen here. We have Mangga knees. We have zinc, cadmium and mercury, and we'll see why those are less than zero or not less than zero equal to or greater than zero. Then we have HF over here in yellow. That's because it's a weird element. There is no real solid like justification for why it's greater than or equal to. Zero is just one of those Ottawa elements out there. But for all the ones that are in Aqua, we'll see the justification of why they have electron affinities that are greater than or equal to zero.

here. The example. Question says Which of the following halogen will have the most eggs? A thermic electron affinity. So remember your halogen are the elements in Group seven a of the periodic table. So if you look at the choices sulfur, neon, nitrogen asked a teen and bro mean Onley. Two of them exist as hell logins and those would be options DNA. So now we have to think about who has the MAWR. Extra thermic electron affinity, which means it's more negative. Remember, as we head to the top right corner, are electron affinity increases, meaning it becomes mawr exo, thermic. So here, bro Ming is higher up in groups of in a So bro mean would have the Mawr excell thermic electron affinity. Now I know it's a little weird. Mawr Excell thermic really means it's a more negative value, but just remember more talking about greatest electron affinity. We're talking about most exile thermic

So let's talk about the exceptions to electron affinity. So the exceptions are elements that possess stable or symmetrical orbital's, and they're less likely to accept an electron. Now remember, as sub shell Orbital's are most stable when they're totally filled with electrons. So here, if we look beryllium, was one of our exceptions. It s orbital is completely filled in. Therefore, it doesn't want to accept another electron. So that's why the electron affinity is greater than or equal to zero. Then remember that P and D sub shells orbital's are most stable when they're half filled or totally filled. Looking at nitrogen, it's P Orbital's air half filled, therefore, doesn't wanna disrupt that stability, so it doesn't want to accept an electron mangga knees. It's D Orbital's are half filled with electrons, so it to doesn't want to accept an electron. Then, finally, zinc in those below it. They have a totally filled in D set of D orbital's, so zinc in the ones below it in terms of the periodic table wouldn't wanna accept another electron. All of these air stable the way they are. They all have either half filled or totally filled peed de or s Orbital's. So just keep that in mind when you see these exceptions to electron affinity in terms of the chart. And remember, for the most part, as we head to the top right corner, electron affinity becomes mawr exo thermic.