Name: イオン性固体 (Ionic solids)
Uploaded: 2021-01-14T10:13:46.000Z
Duration: 7 min 35 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

- [Instructor] Let's talk a little bit about ionic solids,

which you can imagine are solids formed by ions.

So, let's think a little bit about these ions.

So, for example, we could look at group one elements here,

especially things like lithium, or sodium, or potassium.

about these elements wanting maybe not so much

And it'd be pretty easy for them to loose that electron

So, these characters like to lose one electron

the group two elements like to lose two electrons.

While if you go on the other side of the periodic table,

if you look at the halogens right over here,

from having a noble gas electron configuration,

And, if you look at elements like oxygen and sulfur,

they really like to grab two electrons, if they can.

So, what do you think happens if you have some metals

on the left end here mixed with some nonmetals

Well, you might imagine there would be a reaction.

So, for example, if you mixed sodium with chlorine,

the sodiums might lose an electron to the chlorines,

in which case you're going to have sodium cations,

And if the chlorines are now taking those electrons,

And now if you have a bunch of positive ions

They're going to get attracted to each other.

And they're going to get attracted to each other

I like to use sodium chloride as an example

that we see most in our life, this is table salt.

If you were to lick it, it'd taste salty.

But, there's many other ionic salt solids,

many of them would actually be categorized

You could have, for example, a magnesium oxide.

Well, in that situation, the magnesium, each magnesium

so they become a ion with a positive two charge,

and each of the oxygens would gain two electrons.

So then they are anions with a negative two charge.

And these characters once again are going to be attracted

to each other and form an ionic solid in a regular

So let's think a little bit about their properties.

So first of all, let's think about the melting points.

So, these solids, the electrostatic attraction between

And so they tend to have high melting points.

Now what if we were to compare melting points

So for example, if you wanted to compare the melting point

of magnesium oxide which one do you think

Well, as you can imagine the electrostatic attraction,

it's going to be dependent on two things.

The magnitude of the charge and the radius

of the atoms that ae forming this lattice structure.

And the magnitude of the charge here is clear.

Here you have a plus two charge being attracted

to a negative two charge so this has a stronger

electrostatic attraction and so you're going to have

2,825 degrees Celsius, while the melting point of table salt

or sodium chloride is 801 degrees Celsius.

You could also try to compare sodium chloride

Well fluorines are smaller than chlorines and each of them

gain an electron, then the fluoride anion

is still going to be a reasonable bit smaller

Or when you have smaller constituent ions,

the electrostatic attraction is actually stronger.

that the closer two charges are to each other,

the stronger the attractive or the repulsive force,

So, sodium fluoride is actually gonna have a higher

melting point than sodium chloride, by a little bit.

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イオン性固体 (Ionic solids)

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