Periodic Trend: Ionic Radius

for a majority. The periodic trends looking at the periodic table can tell you if they're increasing or decreasing in all our periodic trends were heading towards the top right corner and heading in that direction either increase or decrease that particular periodic trend. Now Ionic Radius doesn't fit into this idea. Ionic Radius does not involve looking at the periodic table. Or let's say Ionic Radius equals the distance between ions, nucleus and its outer shell. And the periodic trend is this. The Ionic Radius increases as the number of electrons of that ion increases. So we're going to say here, when we're looking at Ionic Radius, we're looking at ions and ions. CA need to be positive or negative for positive ions, which are cat ions were going to say cat ions tend to be smaller than their neutral parent form. So what do I mean by this? Well, if we take a look here at lithium, the lithium Adam is one s two to s one. It has one electron in its Valence electron shell. Right, because its second show only has one. When I become lithium ion, I lose one electron. I lose it from that Valence shell. So now the lithium ion no longer has two shells. It only has one shell that contains electrons, and we can see that there is a drop in the size for that particular ion. So just remember, the neutral form of the element is bigger than the cat ion form. So the general trend is losing an electron or electrons causes a decrease in your ionic radius. Now for looking at the and ions and ions tend to be larger than their neutral parent forms. Oxygen is one s two to s to to p four. Here these electrons air in the second shell and there's six of them total. When we become the oxide ion, we gain tomb or electrons. So now my outer shell has eight electrons. It may not be as a parent, but the anti on is slightly bigger than the neutral form. Because why, we said earlier, the Ionic radius increases as the number of electrons increases. So basically, mawr electrons equal larger ionic radius. So we're gonna say gaining an electron or electrons causes an increase in your ionic radius. So just remember, we don't look at the periodic table to determine the trend in Ionic Radius. Instead, we look at the total number of electrons that ion has the mawr electrons. It has the bigger its Ionic radius.

so here for this example question. It says Which of the following statement is false? All right, so the cat ion has a smaller Ionic radius than the calcium Adam. Remember, Adam means it's neutral. Calcium is in group two ways, so it's charges two plus. Remember, we said earlier that cat ions lose electrons, which causes a decrease for the ionic radius off the positive ion. So, yes, since calcium is a positive ion, it will in fact have a smaller Ionic radius than the neutral form. So this is true sulfide ion has a larger ionic radius than these sulfur atom sulfide. I'd means it's an anti on its gained electrons. Remember, we said that an ions are larger than their neutral form because mawr electrons equals larger ionic radius. So this is true. The cadmium ion has a larger ionic radius in the cadmium Adam, so cadmium has a charge of two plus. Remember, cat ions are smaller than their neutral form because they have less electrons. So this is false, and our answer bromide ion. I mean, that's a negative charge. It's an anti on, and ions are larger than their neutral forms because again, mawr electrons equals larger ionic radius. So the only statement here that's false would have to be option C.

here, we're going to say when ranking Ionic Radio I you must determine the total number of electrons for atoms and ions. Now Mawr electrons equals larger Ionic radius. But recall is Elektronik. Species are atoms or ions that have the same number of electrons in those cases. What do we do? Well, if we take a look at this example, it says, arranged the atoms and her ions in order of decreasing Ionic radius. So that means that we need to go from largest Ionic Radius two smallest Ionic radius. So here, if we take a look in step one, it says determined the total number of electrons for each element or ion. Just remember the higher the number of electrons than the greater the Ionic radius. So if we take a look here iron when it is neutral, it has 26 electrons because its atomic number is 26 here. It's lost to, so it's gonna have 24 electrons remaining. Mango knees has an atomic number of 25 so when it's neutral, it has 25 electrons plus one me that's lost one, so it has 24 electrons as well. Nickel has an atomic number of 28 here. It's just lost two electrons, so it has 26 remain. And then finally, here we have zinc. Zinc has an atomic number of 30 so when it's neutral, it has 30 electrons, plus two means. Now it's lost to, so it only has 28 electrons remaining. All right, so we can arrange this somewhat from largest to smallest. We know that zinc two plus ion will be the largest because it has the most electrons, followed by nickel. But how do we break the tie between iron two plus and manganese plus one? That's where Step two comes into play. If the atoms or ions have equal electrons, meaning there is Elektronik, then the more negative the charge, the larger the Ionic radius. So we're gonna say for an Ionic for is electric species We just said the greater than negative charge than the greater the Ionic Radius. So a negative three charge will be bigger than a negative to charge bigger than a negative one bigger than zero bigger than plus one plus two plus three. Now, of course, you could have some species that have a charge that's outside of negative three or beyond plus three is well, same rules would apply. So both iron two plus and manganese plus one have 24 electrons. But Mangga Nis plus one is bigger than plus two. So we'd say that Mangga Nis plus one ion is bigger than iron two plus ion. So just remember, when it comes to ions mawr electrons equals larger ionic radius. If they're tied, then we look at the charge to break that tie, the more negative the charge, the larger die Ionic radius will be.