Lesson video

- Hi, I'm Ms. Barrett from the Oak National Academy.

Today's lesson is all about elements And this is from the atoms and the periodic table unit for Key Stage 3.

Make sure you've got a periodic table with you for today's lesson, 'cause that's gonna really help you.

Let's get started.

So in this lesson, we are going to define an element and learn how different elements are represented by chemical symbols.

So some key words for the lesson.

An atom is the smallest unit of matter.

You might have heard of atoms before.

But don't worry if you haven't, 'cause we're gonna have a little recap in a minute.

A tiny piece of matter is called a particle.

And metals are substances that are usually solid, hard, shiny and good conductors of electricity and heat.

So the outline for today's lesson on elements.

We're gonna start with defining an element.

And then we're gonna have a look at some chemical symbols.

Then we're gonna have a bit of an introduction to the periodic table.

And then we're gonna talk about metals and non-metals.

So let's get started with defining an element.

So we're gonna start with talking about atoms. As I said, you might have heard of atoms, but you might not know what they are.

So atoms are the smallest unit of matter.

So if we were to chop an object into the smallest pieces it could possibly be until you couldn't divide it any further, there's pieces you wouldn't even be able to see them.

This would be atoms. They are the smallest unit of matter.

And everything in the world is made from atoms. So whether that is the paper that you've got in front of you, a pen, the screen that you are looking at, your body, your hair.

Everything is made from atoms. And this is why atoms are so, so important.

In this lesson, we are going to represent atoms as circles of different sizes and colours, just like the pictures you can see here.

So here we've got some particle diagrams. On the left, these are elements.

On the right, these are not elements.

So what do you think defines an element? What can you see the differences between these two particle diagrams? So on the left hand side, you can see that the elements are made from one type of atom.

The grey solid.

There's only one type of atom there.

And then we've got a gas where the particles or the atoms are all black.

Again, that is one type of atom.

Whereas on the right hand side, we've got a liquid that is made of grey and white particles.

And then we've got another solid that's made of two different types of particles or two different types of atoms. So when there is more than one type of atom, that is not an element.

An element is a substance made of one type of atom.

So elements can be solids.

They can be liquids or gases, just like we saw on that previous slide.

So remember your passcode diagrams for these three elements.

So solids have fixed regular arrangement.

Liquids are particles are really close together.

But they haven't got a fixed or regular arrangement.

And a gas, they have their atoms completely separated.

Nothing is touching.

So it doesn't really matter what state the element is.

If there is one type of atom there, then it is an element.

So a copper pipe is made from copper atoms only.

If we were able to zoom in really, really, really far, all the way until we can see the atoms, which isn't actually possible.

But if we could, this is what it might look like.

It's solid.

And you would see all the copper atoms. They look exactly the same, all lined up in that regular arrangement.

And the same fill this piece of charcoal.

If we zoomed on that one, you would see carbon atoms all lined up.

And every single one of them would be the same.

So copper and carbon are both elements.

So let's check how much we understood so far.

An element is a substance made of two or more types of atom.

Is that true, or is that false? Have a think and also have a think about how you would justify your answer.

Okay, so an element is a substance made of two type or more types of atom.

Is that true? Nope, that is false.

Remember, an element is a substance that is made of one type of atom, not two.

It can only be an element if there is only one type of atom.

Next question.

Which of the following diagrams shows an element? So think carefully, what about our definition of an element? And have a think which one that applies to.

Okay, do you think you've got it? The correct answer is C.

That one is our element, because that's the only one that has one type of atom.

A is a molecule that's got a large grey atom and two smaller black atoms. But they are different.

And in B, there is a mixture of the white and black atoms. So that is also not an element.

Okay, so onto your first task for the lesson.

So in the first part, you are going to circle the boxes that show an element.

So just like we did in that check for understanding task, have a little look, which one do you think matches the definition of an element? And then part B, complete the sentence.

An element is- Fill in the rest of the definition.

Pause the video here.

Have a go.

Come back when you're done.

Okay.

How did you get on? Hopefully, you didn't find that too difficult.

Let's go through the answers.

So the boxes that showed an element were A, D, F and G.

And you can see that these are the only ones that have one type of atom.

Even though A is a gas, D is a liquid, F is a gas as well, and G is a solid, that doesn't matter.

They all have one type of atom present.

That means they must be an element.

And then of course, our definition is an element, is a substance, made from one type of atom.

Right.

So let's move on to our second part of the lesson.

This is on chemical symbols.

So each element is represented as a symbol.

So here we've got the symbol for hydrogen.

And hydrogen symbol is a capital H.

And it's just the one letter.

On the right hand side, we've got aluminium.

And aluminium symbol is a with A little l.

So some elements are represented by one letter.

Some of them have two.

But the most important thing is that first letter in the symbol is always uppercase.

And if there is a second, then that one is always lowercase.

So chemical symbols are used on the periodic table.

You might have seen this before.

This is the periodic table.

And these are all the symbols of all of the 118 elements that we know.

So let's see how much we've understood about chemical symbols.

What you're gonna do here? There are four elements with symbols.

And I want you to spot the mistake in the chemical symbol.

Pause the video if you need to.

Okay.

So in that first one, hydrogen.

What did I say the symbol for hydrogen was? Because it definitely wasn't Hyd.

The symbol for hydrogen, it's actually just an H.

So the important rule to remember there is chemical symbols have up to two letters.

And sometimes, it's just one, depending on what element it is.

So that was the mistake there.

The next one, we've got magnesium.

What was the mistake here? Well, magnesium symbol is Mg.

But the second letter has to be lowercase.

So that was the mistake on that one.

The next one, nitrogen.

The symbol for nitrogen is N.

But remember that that first letter always has to be uppercase.

And then finally, we've got potassium, and we've got capital P.

And you might first look at that one and think, I can't really spot the mistake here.

But if you have a look at the periodic table, and you find potassium, or you find P, you'll realise that these two don't match.

And actually, the symbol for potassium is a K.

So the symbol doesn't always match the name.

So you might think it's potassium, it must be P.

But sometimes, they're based on old names or based on Latin names, so the symbol is completely different to the name.

So watch out for that one.

Okay, next question.

What is the symbol for beryllium? And again, if you need to pause the video and have a look at your periodic table, that's absolutely fine.

All right.

Did we get that one? So the symbol for beryllium is Be.

So sometimes, the symbols can be quite similar.

So B is actually boron, and Br is actually bromine.

So they're all existing elements.

But the symbols are just ever so slightly different.

Next one, what is the symbol for silver? Okay, so on this one, the right answer is Ag.

So that's a bit of an unusual one.

S is actually sulphur, and Si is actually silicone.

Even though they would seem like they should match up with silver.

As I said, sometimes, you've gotta be careful that the symbols are not quite what you would expect.

Right.

Onto Task 2.

So for this task, you're going to use your periodic table to fill in the blanks.

So some of them have the symbol, but no name.

And some of them have a name, but no symbol.

So you need to fill them up so that everything has a symbol and a name.

Pause the video here.

Have a go.

Best of luck.

Right.

How did you find that? Hopefully, you found that okay.

Let's go through the answers.

So the first one, we've got He.

So what element did you find that was on the periodic table? That is helium.

The symbol for calcium is Ca.

And then we've got an O.

What's that the symbol for? That was oxygen.

Carbon.

Carbon is a C.

N.

We had this one earlier.

Did you remember what that one was? That one was nitrogen.

Lithium.

Symbol is Li.

Hg.

Now this is a strange one, 'cause it doesn't match the word.

This was mercury.

It's in the transition metals down the bottom of the periodic table.

So you might have struggled to find that one.

Another strange one.

Lead, the symbol is Pb.

Au.

This is gold.

Now, I bet you've come across gold quite a lot.

But you probably didn't know that its chemical symbol was Au.

And then finally, tin symbol is Sn.

So you can see those last four are all symbols that don't really match the name, so they're ones to look out for.

Really well done if you got those right.

Let's move on to the next section of the lesson.

So we're onto the third part now, introduction to the periodic table.

So there are 118 elements in the periodic table.

And this periodic table shows all the elements that we currently know.

There might actually be more elements.

We just haven't discovered them yet.

So the elements are arranged into groups and periods.

So the groups are the columns of the table.

So you can see here, from 1 all the way to 0 in blue, the groups are downwards in columns.

And then the periods, these are the row, so going across.

So you can see here, we've got seven periods in the periodic table.

And then the block in the middle, these are known as the transition metals.

These have some quite complicated properties.

So we don't tend to talk about transition metals too much at Key Stage 3.

So if you've got your periodic table in front of you, I would suggest you write on these numbers to indicate what the periods are and what the groups are, because that will help you for the next part of the lesson.

Okay.

So have you got your periodic table? Let's answer some questions.

Which element is in period 4 and group 2? I'll give you a few seconds to find it.

So that one is calcium.

Did you get that right? Well done if you did.

Which element is in period 2 and group 6? Is it barium, nitrogen or oxygen? So that one is oxygen.

Well done if you've got that one right.

Some people sometimes get the groups in periods the wrong way round.

So just make sure that you know the periods are across, and groups go down.

Next one, which element is in period 3 and group 5? So that one is phosphorus.

Well done if you've got those right.

Let's move on to the task.

So the first part of the Task 3, you're gonna complete the sentences about the periodic table.

So the rows are called something.

Columns are called something.

And the block in the middle is called the something.

Pause the video here.

Have a go.

Good luck.

Okay, shall we go through the answers? So let's complete the sentences.

Rows are called periods.

Columns are called groups.

And the block in the middle is called the transition metals.

Give those a tick if you've got those right.

Well done.

Okay, let's move on to part B.

So in this part, we're going to find the element.

The first three questions are similar to the check for understanding task we did earlier.

And the last two parts, you need to find the transition metal in periods 4 and 5.

Pause the video and come back once you have completed the task.

Right.

Let's go through the answers.

How did you get on? So the first one, period 1, group 8, you should have found that was helium.

And whether you wrote the word helium or use its chemical symbol, He, either would be acceptable there.

And the next one, period 3 and group 5.

That one was phosphorus with a capital P for the chemical symbol.

Period 5, group 7, which element was that? That was iodine.

Iodine has a capital I for its chemical symbol.

And in the next one, there are many options you could have had for the fourth and fifth question.

So you needed to find the transition metal in period 4.

So that was any element from scandium to zinc.

So remember the transition metals are the block that are in the middle of the periodic table.

So you could have had scandium, you could have had titanium, vanadium, chromium, anything between scandium and zinc.

And the same applies to the next question for period 5.

This was any element from yttrium to cadmium.

So you could have had yttrium, zirconium, rhodium, palladium, anything along that period.

Well done.

Hopefully, you got those correct.

So for our final part of the lesson, we are going to look at metals and non-metals.

So you might have heard of metals before.

You probably know what a metal is.

But we're gonna talk through some different types.

So the periodic table is divided into metals and non-metals by a stepped line.

So it starts between boron and aluminium and then steps all the way down, as you can see, on the diagram.

So if you've got your periodic table in front of you, I would suggest drawing this line on if it's not already there, 'cause that's gonna really help you identify which ones are metals and which ones are non-metals.

So everything to the left of that step line are metals.

Everything to the right of that step line are non-metals.

So as you can see, there are a lot more metals on the periodic table than there are non-metals.

So how would you group these elements into metals and non metals? So we've got gold.

We've got oxygen.

We've got carbon which is charcoal.

And we've got a silver ring.

So which ones do you think are metals, and which ones do you think are non-metals? So the metals are gold and silver.

These are two quite common metals.

A lot of jewellery is made out of gold and silver.

So you might have heard about these or come across them.

And then on the right hand side, we've got the non-metal.

So carbon, this version of carbon is a black solid.

And then oxygen is a gas.

So inside that gas canister will be a gas.

And it's usually in the air.

We can't see it.

And that is not a metal.

Okay.

So using your periodic table, you're going to work out if the krypton is a non-metal.

Is that true, or is that false? And then make sure you justify your answer.

Okay, so that one was true.

Krypton is a gas.

And it's found on the right hand side of the periodic table.

It's part of group 0 which are called the noble gases.

So it's definitely not a metal.

Okay.

So let's move on to Task 4.

So what you're gonna do in the first part is you're gonna sort the elements into the correct columns in the table.

So I've got eight elements here.

And you just need to have a look at your periodic table and decide which ones are metals and which ones are non metals.

Pause the video here.

Have a go.

And I'll see you once you're done.

Okay.

Hope you got on okay with that.

Let's go through the answers.

So the metals were caesium, magnesium, cobalt and thallium.

So that must mean the non-metals were neon, arsenic, chlorine and sulphur.

Give those a tick if you've got those right.

And if you've got any the wrong way round, make sure that you have put them back into the right columns.

Okay.

Let's move on to part B.

So use your periodic table to find the element name and chemical symbol that matches the statement.

So the non-metal in period 7.

The metal beginning with a V.

The non-metal in group 3.

The metal in group 7.

And the metal in group 2 and period 3.

So again, use your periodic table to find these.

And make sure that you've got that metal and non-metal step line written on your periodic table, 'cause you're gonna need that to help you with this task.

Pause the video.

Good luck.

Okay.

Let's go through the answers.

So the non-metal in period 7, there is only one non-metal in period 7, and that was oganesson.

So that chemical symbol is Og.

The metal beginning with V.

Well, this one is in the transition metal block.

and this is vanadium.

And that chemical symbol is a V.

So that was a little bit of a clue there.

The non-metal in group 3.

So remember the groups go downwards.

And the only non-metal is boron.

That chemical symbol is a B.

The metal in group 7.

So group 7 is mostly non-metals.

But there is one metal right at the bottom, and that is tennessine.

And that chemical symbol is Ts.

And the metal in group 2 and period 3 was magnesium with the chemical symbol Mg.

Really well done for making it through all of those tasks.

That was our last task for the lesson.

You've done a fantastic job on the first lesson of this unit.

So let's summarise everything that we have learned today.

An element is a substance made from one type of atom.

A chemical symbol is a one or two letter representation for an element.

The periodic table is arranged into periods and groups.

Elements with similar properties are in the same group.

The periodic table can be split into metals and non-metals.

And that is the end of the lesson.

Have a go at the exit quiz and see how much you've learnt.

Well, I hope you enjoyed today's lesson, and you've got loads of new chemistry knowledge.

Well done for completing all the tasks.

You've done really, really well.

Thank you for using the Oak National Academy.

And I'll see you next time.