Lesson video

Hello, my name's Mrs. Clegg, and today I'm going to be helping you learn about the properties of Group 0 elements.

This is part of the unit: Groups of the Periodic Table.

We're gonna be looking at where Group 0 are on the periodic table.

We're gonna be looking at some of the uses in our everyday world for Group 0 elements, and we're also gonna be looking at the electronic structure.

Now, it would be really helpful if you've got a periodic table to sort of refer to.

So if you haven't got one, go and get one.

Pause the video and join us when you're ready.

And so the outcomes for today's lesson are, that by the end of it, we should feel much more confident about being able to describe some of the applications or uses for Group 0 elements and explain how their properties are determined by their electronic structure.

So let's get going.

Here are some of the keywords for today: inert and noble gas.

And here's the words written into a sentence.

You might want to pause the video and make some notes for yourself here about these two words.

So I've split today's lesson up into two parts.

The first part we'll look at electronic structure.

And the second part we'll look at those properties and uses of Group 0 elements.

So let's get going with the electronic structure.

So here's a periodic table.

You should all be quite familiar with this by now.

If you look at the top, you'll see the numbers, the group numbers.

At the far right hand side here, we've got Group 0.

And the elements in Group 0, you can see there are helium, neon, argon, krypton, xenon, radon, and oganesson.

Make sure that you can recognise the symbols there.

Let's just have a quick check.

Which of these symbols represents elements from Group 0? Well done if you said neon, A, and well done if you said C, xenon.

If you said rhodium, B, that's a transition metal, so not Group 0.

Here's another check.

So here's a statement.

The elements in Group 0 are helium, nitrogen, argon, krypton, xenon, radium, and oganesson.

Is that true or is that false? Hopefully you know it's false.

Can you justify why you've said it's false? And you should notice that it's B, Group 0 elements do not include nitrogen and radium.

Nitrogen's in Group 5 and radium's actually in Group 2, Group 0 elements are gases at room temperature.

Room temperature's, you know, round about 20 to 22 degrees centigrade usually.

So they're normally all gases at room temperature, and oganesson is an exception.

So here's some facts about oganesson because you might not come across that before.

It's highly radioactive.

Only a very few atoms have ever been made.

And so we don't know a lot about the chemical properties of oganesson.

We expect it to be a solid at room temperature.

And some of the physical properties like boiling point and density have been predicted.

Group 0 elements are also called the noble gases as they're very unreactive or inert.

There's both of the keywords for today's lesson there.

So Group 0 elements, we call them noble gases because they're very unreactive.

And that's due to the number and arrangement of their electrons.

So helium, if you've got a periodic table beside you, find it and you will see that helium has an atomic number of two, which means it has two protons, and therefore two electrons.

Find neon on your periodic table now.

And neon has 10 protons, atomic number 10 and 10 electrons.

So let's think a little bit more about those.

So all the Group 0 elements have a full outer shell of electrons and that makes them very stable as they don't need to lose, gain or share any electrons.

So they're very stable and unreactive.

So here's helium.

And helium has two electrons, remember.

And those fill the first electron shell.

The first electron shell, if you remember, can hold up to two electrons.

Here's neon, it has 10 electrons.

And so we fill the first shell with two electrons and then the second shell is also full with eight electrons.

So two plus eight equals 10.

And the second shell can hold up to a maximum of eight electrons.

So which of these atoms could actually be in Group 0? Have a look at the structures carefully and make a decision, which atom or atoms could be Group 0? So which have you said? So if you said A, well done.

If you have a look at that, it has got a full outer shell.

Look at the outermost ring, the outermost shell, it's got eight electrons and we have a quick check and all the electron shells are full.

B, it hasn't got a full outer shell, so that can't be in Group 0.

And C looks like it should be in Group 0, but unfortunately the first shell is not full.

So that diagram's been drawn incorrectly.

So the answer's A.

So I want you now to have a look at neon again and tell me how many protons and electrons neon has.

And then draw the electronic structure of neon using the shells and the crosses to represent the electrons.

Pause the video and come back when you're ready.

So here's neon on the periodic table.

So it has 10 protons, 10 electrons, and so the electron structure would look like this, two in the first shell and eight in the outer shell, the second shell.

So let's have a look at argon now and do the same thing.

Pause the video and come back when you're ready.

Here's argon.

It has 18 protons and 18 electrons.

And the electron structure would look like this.

So it's got three shells and the outermost shell has got eight electrons.

The second shell has eight electrons, and the inner first shell has two electrons.

And all of those add up to 18.

Well done if you've got those correct.

So let's have a look at Task A.

Here, we've got a table to complete.

We've got the Group 0 elements, we've got the number of protons, the number of electrons, and then their status at the outermost shell.

That's just to say whether it's full or not full.

So pause the video and have a go at this and come back when you're ready.

Let's have a look at the answers.

So argon, 18 protons, 18 electrons, and that would have a full outer shell two, eight, eight.

Well done.

Radon, we know it's got 86 electrons, a full outer shell.

And so if it's got 86 electrons it will have 86 protons.

Okay.

The next line, a mystery element.

So you might have wanted to use your periodic table here to have a look and see what element that might be.

And it was xenon.

So if it's got 54 protons, it's got 54 electrons, and because we know it's Group 0, it will have a full outer shell.

Krypton, the periodic table will tell you it has 36 protons, 36 electrons, and a full outer shell.

And the last mystery element at the bottom there has two electrons, therefore it'll have two protons.

Atomic number two is helium and that will be a full shell.

Well done if you've got all of those correct, there's a lot to think about there.

So we're gonna move on to the second part of our lesson today, their properties and uses.

Group 0 elements exist as colourless, monotonic gases at room temperature and pressure.

Let's just have a little think about that word "monoatomic".

So mon or mono means single, so single atoms. So Group 0 elements exist as single atoms at room temperature and pressure.

The atoms don't need to bond with other atoms to make molecules as they have this full outer shell of electrons and that makes them very stable.

It also makes them chemically inert or unreactive, one of our keywords today.

So here is a bar chart about boiling point and what's interesting is to learn about the trend here.

On the bar chart, at the bottom on the X axis, we've got the elements, helium, neon, argon, krypton, xenon and radon.

And on the Y axis we've got boiling points.

If you look at the top of the Y axis, that's zero degrees C.

And what you'll notice is that as we go down the group, so helium's at the top, radon's towards the bottom, as we go down the group, boiling points increase.

That means they become closer to zero degrees C.

That's an interesting thing to remember, an interesting trend to remember.

So let's have a quick check.

Which Group 0 elements have boiling points lower than krypton? You might like to use your periodic table here to look at where krypton is in Group 0.

Well done if you said helium and argon and neon, they all have boiling points which are lower than krypton.

Remember the trend, boiling point increases as you go down the group.

So the increase in boiling point is due to this.

Atoms increase in size as we go down the group.

So helium would be the smallest atom.

And because of that, the forces of attraction between these larger atoms are stronger.

And so more energy is needed to overcome these stronger forces towards the bottom of the group.

And here we've got a graphic to help you, and you can see the forces of attraction between them.

And here we've got two larger atoms, and the forces of attraction here are stronger between them.

So quick check.

Molecules of the Group 0 elements have weak intermolecular forces.

Think about that one.

Is it true or is it false? Well done if you thought it was false.

And can you justify your answer? What would be a good statement to say here.

"It is false because.

." Option A is correct.

Group 0 elements are monoatomic and they have weak forces between their atoms. Group 0 elements also show a trend in density.

And remember, density is the mass of a substance per unit volume.

And Group 0 elements are gases, so their particles are spaced out, and so they all have low density because there's the large volume there.

They're spaced apart, their particles.

And this is really useful in balloons, for example.

Helium is used a lot in balloons because it's less dense than air and so it will float.

So quick check.

Going down the group, the mass of Group 0 elements' atoms, do they decrease, show no pattern or do they increase? So the mass of Group 0 elements.

Hopefully you've said they increase because remember, they get larger, so the mass is going to increase.

Here we've got a chart showing density and you can see that there's a clear trend there in terms of density.

It increases as we go down the group, and that helium is at the top of the group, and radon's towards the bottom.

Helium has a low density and radon has a higher density.

So we've got another trend there.

The density increases as we go down the group.

Density increases as the mass of the atoms increases.

So a quick check.

A balloon is filled with neon.

Neon has a density of 0.

9 grammes per decimeter cubed.

If air has a density of 1.

2 grammes per decimeter cubed, what would happen to the balloon? Would it float upwards, would it sink downwards, or would it sort of stay in one place? What do you think? It would indeed float upwards because neon has a density which is less than the density of air.

So it would float.

Group 0 elements have similar chemical properties.

They're all non-flammable.

And that's really, really useful.

So argon, for example, is used to provide an inert, unreactive atmosphere when we're welding.

And argon and xenon are used in light bulbs, which get very hot.

Here's a quick check.

When a lit match is placed in a jar of helium, it will cause an explosion.

Is that true or is that false? It's false because.

Can you justify your answer? Which one of those is the right justification? It's B, because helium, as with all Group 0 elements, is non flammable.

Group 0 elements cannot conduct electricity as they don't have any free or delocalized electrons to carry charge.

But what they do do is glow when you pass a high voltage through them and they don't decompose.

And this is a really useful property.

In signs, for example, neon is used in a lot of signs that you'll see around the place.

Xenon is used in car headlights, and krypton is used in lasers.

So three uses there of Group 0 elements, because they don't conduct electricity.

So which test could we use for a Group 0 gas? Which one of these would be useful to be able to test an unknown gas to see if it was Group 0? Indeed, it's option C.

Option A is the test for hydrogen gas, option B is the test for carbon dioxide gas, and option D is the test for oxygen gas.

Other uses of Group 0 elements are double glazing.

Krypton is a good thermal insulator, and radon is actually highly radioactive and is used in radiotherapy to treat cancer.

What key properties does krypton have which explain why it's useful in double glazing? So have a look at all of these properties and which ones are particularly useful for double glazing? It's useful to be colourless because it's a window, it's useful for it to be unreactive, and it's useful to be a good thermal insulator.

Well done if you got all three there.

So let's have a go at Task B.

We've got a table of data here and we can use that data to estimate the missing information.

We can predict the values for other members of the group.

So for some, you might like to use your periodic table and others you just need to remember some of the trends that we've just talked about.

So what were the trends for the size of the atoms? What were the trends for boiling point? What were the trends for density? Stop the video and come back when you're ready.

Okay, let's have a look at some of the answers.

So helium has a relative atomic mass of four, which you could find in the periodic table.

If you look for the relative atomic mass on your periodic table, you'll find neon.

And it's 20.

And the atomic radius, PM in brackets there at the top, that means picometers, that's a unit of measurement.

And remember the trend in terms of atomic size, increasing as we go down the group.

So it's going to be more than 31 and less than 71.

So 38 is the answer.

But anywhere between 31 and 71 would be fine, because it's an estimation.

And then density, remember also that density increases as we go down the group.

So it will be somewhere between those two figures, 0.

18 and 1.

78.

So that's a good estimate.

0.

85 to 1.

00.

Argon, okay, has a boiling point minus 185 to minus 200.

Krypton, we can find out, has a relative atomic mass of 84, and density will be more than argon but less than xenon.

Boiling point in xenon will be between krypton and the missing element at the bottom there.

And the missing element is, of course, radon.

Well done if you've got all those right.

Remember you won't have exactly the same data as me because it's an estimate.

Let's do another question.

Well, there's two questions here.

2a and 2b So we're doing a matching exercise for the top one, and then looking at some examples of the use of glowing in 2b.

So stop the video, have a go at those when you're ready.

So here's the answers.

You might like to stop the video to check your answers here because there's quite a lot of information on there.

But helium is less dense than air, and so it has good use in party balloons.

Trace the lines.

Krypton is a good thermal insulator and so therefore it's useful in double glazing.

Radon is radioactive and used in radiotherapy and I think I missed argon out, which is unreactive, so it's very good for welding.

And then 2b.

So three examples for the use of the fact that element Group 0 elements glow when a current is passed through them.

And we've got the shop signs for neon, we've got xenon in the car headlights and we've got krypton with lasers.

Well done.

So here's our summary.

Group 0 elements are called the noble gases, or inert gases because they're very unreactive with other elements.

Group 0 elements have a full outer shell of electrons.

The atomic mass, density and boiling points of Group 0 increase down the group.

And Group 0 elements emit coloured light when a high voltage is applied to them.

They glow, they don't decompose.

Well done for your learning today.

There's a lot of information there and I hope you're feeling a lot more confident about the properties and the electronic structure and some of the uses.

So the key thing is to remember those trends.

Well done.

And I'll see you next time.