Consider the ions Sc^3+, Cl^-, K^+, Ca^2+, and S^2- . Match these ions to the following pictures

step 1 Okay, so first we're going to be looking at some different ions. I'm going to write down some io

Consider the ions Sc^3+, Cl^-, K^+, Ca^2+, and S^2- . Match...

Key Concepts

Periodic Trends in Ion Sizes

Periodic trends play an important role in predicting and comparing ion sizes. Generally, cations (positively charged ions) are smaller than their parent atoms due to the loss of electron-electron repulsion, whereas anions (negatively charged ions) are larger because of the added electron-electron repulsion. Understanding these trends helps in deducing the relative sizes of various ions based on their positions in the periodic table and their charge states.

Effective Nuclear Charge

Effective nuclear charge is the net positive charge experienced by an electron in an ion or atom, taking into account both the actual nuclear charge and the shielding effect of other electrons. A higher effective nuclear charge tends to pull electrons closer to the nucleus, leading to a smaller ionic radius, while a lower effective nuclear charge allows the electron cloud to be more extended, resulting in a larger ionic radius.

Ionic Radius

Ionic radius refers to the effective distance from the center of an ion's nucleus to the boundary of its electron cloud. This concept is fundamental in understanding the relative sizes of ions, as differences in the number of electrons, nuclear charge, and electron-electron repulsion all affect how far the electrons extend from the nucleus.

Isoelectronic Series

An isoelectronic series consists of ions or atoms that have the same number of electrons but different nuclear charges. In such series, the species with the greater nuclear charge usually holds its electrons more tightly, resulting in a smaller ionic radius compared to others, even though they have identical electron configurations.

Transcript

00:03 Okay, so first we're going to be looking at some different ions.

00:06 I'm going to write down some ions here, and i'm going to do it in blue because it's my favorite color.

00:11 And so hopefully there isn't anyone that's red or that's, i guess they wouldn't.

00:15 We're good.

00:16 Okay, so blue.

00:17 So i'm going to write down just a list of ions here.

00:21 And remember, ions are atoms that have a different, that have a specific charge to them, a different charge than what they normally would have, due to either.

00:34 Taking away or adding electrons to its, to that specific atom.

00:40 So, for example, let's say that we have oxygen.

00:43 Okay, now oxygen, let's say that we give it a negative two charge.

00:49 Let's say that we have fluorine, and i want to give it a negative one charge.

00:53 So these are now ions.

00:55 Oxygen has, in this ion, would have two extra electrons there.

00:59 Floreen would have one extra electron.

01:03 Let's say that we have sodium with a plus one charge and magnesium with a plus two charge.

01:16 And let's say, let's just add one more in there just to make it fun.

01:22 Let's see.

01:23 Which one do i want to use here? let's looking at my thing here.

01:34 Let's do aluminum, okay? so i'm going to put aluminum and let's give it a plus three charge there.

01:46 Okay.

01:48 So with this, i've got one, two, three, four, five different ions there.

01:52 The question that we can look at now is size.

01:55 Which one of these has, which of these ions has the biggest and small size? i'm going to do this in green.

02:02 So let's do biggest to smallest.

02:05 And when we're doing this, we want to look at a, there's a general rule that you.

02:08 You will follow here.

02:09 And the main rule that you want to follow is, well, there's two rules, and i'll just, i'll explain those to you right now really quick.

02:16 So when we're looking at the periodic table, when we're looking at size, generally if you're looking at, if you look, there's these different rows, and i can't draw very well.

02:26 But each of these are not rows, but columns.

02:29 These columns are groups, and as you go down a group, that actually will, we see a trend of increased size...

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