Hello, my name's Mrs. Clegg, and today we're going to be learning about the transition metals.

This group contains most of the metals that we find on the periodic table, and some very familiar ones in there like silver, and gold, and iron, and copper, and some very unfamiliar ones too.

This lesson is part of the unit called industrial chemistry.

Let's start the lesson.

And here's the outcome for today's lesson.

You should feel by the end of it that you can describe the physical and chemical properties, and some uses of transition metals, and be able to compare them to Group 1 metals, the alkaline metals, sodium, lithium, potassium, et cetera.

So let's get started.

Here are the key words for today's lesson I want you to listen out for.

So transition metals, catalyst, ion, and density.

And here are those words written into sentences.

You might like to pause the video, and make some notes for yourself.

Today's lesson is split into two parts.

We'll look at the physical properties of transition metals first, and then we'll look at the chemical properties.

So let's get started with the first part of the lesson.

Now, transition metals are found in the centre of the periodic table, between Groups 2 and 3 here.

It might be helpful to have a periodic table to hand throughout the lesson.

Have a look at the periodic table there, and familiarise yourself with some of the symbols.

The transition metals are not unusual in terms of their physical properties.

They're very similar to most metals.

So they're malleable.

That means they can be bent or hammered into shape without shattering.

They're ductile and that means that they can be drawn out into long wires without snapping or breaking.

They're good conductors of heat or electricity.

They're shiny.

Sonorous, that means if you tap them, they've got a ringing sort of sound.

High density.

And they have high melting, and boiling points, other than mercury.

And mercury is a liquid at room temperature.

It actually has a melting point of minus 39 degrees centigrade.

Some metals are magnetic, iron, cobalt and nickel.

They are magnetic.

And while some transition metals exhibit these magnetic properties, it's not universal.

Not all the transition metals are magnetic at all.

And some uses of these metals which are magnetic, include generators, transformers, loudspeakers, being powerful permanent magnets, computer hard drives, and electric motors.

Transition metals tend to be stronger, and harder, and denser than our Group 1 alkaline metals, and they have higher melting points.

Let's have a look at some of the data to show this.

So in the first column there I've got potassium, which hopefully you recall is Group 1, and the rest are all transition metals.

So look at the difference between melting point, density, hardness and tensile strength there.

There's quite a difference in the pattern, isn't there? And due to the physical properties that transition metals have, they're used a lot in construction and manufacturing.

And here are some examples.

So chromium is used in stainless steel.

And manganese is used to improve the toughness of steel.

Iron is used in building materials.

And if you look at the image you can see the rods there giving structure and strength to the building materials.

Cobalt is used where we need really high-strength alloys.

For example, in a jet engine.

Nickel is used in coin making, and copper is used in electrical wiring.

So let's do a quick check.

Which of the following statements about transition metals is true? So I'll give you a moment to read those.

Okay, let's have a look.

So it is B, well done.

So if we look at some of the other responses.

If we look at A, remember Group 1, those metals were very soft.

Remember we could cut them with a scalpel.

If we look at C, transition metals include metals in Group 2 and 3.

Transition metals are in a block between Groups 2 and 3.

Look at your periodic table.

Transition metals are much stronger than Group 1 metals.

So I've got some students here discussing transition metals, and what I'd like you to do is identify, first of all, who's correct, and update any incorrect statements.

So rewrite them so that they are now correct.

I'll give you a moment, pause the video, and come back when you're ready.

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

So the correct statements.

There's two correct statements from Alex and Jacob.

Transition metals are shiny, and used in coins like copper and nickel.

Jacob said, "Transition metals are good conductors of heat and electricity", which is true.

So let's have a look at Aisha and Izzy's statements, and make them correct.

"All transition metals are not magnetic," so iron, nickel and cobalt are magnetic.

And Izzy, "Transition metals are used in construction due to their high strength and other useful properties." So let's move on to the second part of our lesson now, looking at the chemical properties of transition metals.

Transition metals can form ions with different charges.

And this is because their atoms can lose different numbers of electrons.

So iron for example, can form both Fe2+ and Fe3+ ions.

Iron can either donate two electrons or three electrons.

And depending on how many electrons they've transferred, it will change their properties.

So here we've got a compound containing Fe2+ ions.

So the iron atom has transferred two electrons.

You can see that it's pale green.

And here we've got a compound with Fe3+ ions in it.

And it's a very different colour, isn't it? Orangey-brown.

So iron hydroxide for example.

Or you could have this compound, iron oxide.

Rust in other words, this reddy-brown colour.

They're also known for their ability to form coloured compounds and solutions.

And actually a lot of paints, and pigments contain transition metal compounds.

So this compound, this picture here, this blue powder, is a compound containing copper 2+ ions, and most other metals form white compounds which become colourless when in solution.

So if you think about sodium chloride.

When you add that to water, it will produce a salty solution, which is colourless.

Chromium is another transition metal, and that can also form multiple ions.

And the two common ones are chromium 2+ ions, which is a lovely blue colour, or chromium 3+ ions, which is a green colour.

So they're compounds, so chromium compounds could be blue, or they could be green.

In order to distinguish between these ions, we tend to use Roman numerals.

So chromium II in the brackets there refers to chromium 2+ ion, and chromium with the three Roman numerals in brackets refers to chromium 3+.

Manganese can also form multiple ions, and the common ones there include manganese 2+ ions, which is lovely pink colour.

And here we have a lovely purple solution which contains manganese 7+ ions.

You can see why paint and pigments include a lot of transition metals can't you? Transition metal compounds that contain the same metal ion can have different colours depending on which other ions are present.

So copper is an example.

Here we've got copper sulphate.

So we've got the copper 2 ions, 2+ ions, lovely blue colour, and here we've got copper, 2+ ions as well, but it's black copper oxide.

Let's have a quick check.

Each transition metal can only form one ion.

For example, iron only forms Fe2+.

Is that true or is that false? Yes, it's false.

Can you justify your answer? And I'll give you two statements to help.

Yes, B.

Amazing if you got that right, well done.

Now the chemical formula for transition metal compounds can also vary and get quite complicated, because of the multiple ions that a metal can conform.

Because for example, iron can form both Fe2+ and Fe3+ ions.

Let's have a look at some examples.

So iron II chloride, the two in the Roman numerals there tells us that this iron ion is Fe2+.

And if you think about that, remember chlorine, have chlorine atoms have seven electrons over the outer shell.

So they need to gain an electron to become stable.

And so the iron would donate an electron to each of those chloride ions.

Then we've got iron oxide and iron nitrate.

But we can also form iron III chloride, iron III oxide, and iron III nitrate, which is why it's important to be using the Roman numerals.

Unlike Group 1 metals, transition metals react really slowly with water, or they don't react at all.

If you remember back to Group 1, when we were looking at them reacting with water, we only had to put a small rice-size piece on the water and it was whizzing around giving off hydrogen gas, and forming hydroxides.

Group 1 also formed oxide when they're left in the air.

Remember most of them are kept in bottles of oil to keep them away from oxygen.

And they will also react very well with halogens, Group 7, to form metal halides.

So transition metals, they do form oxides when they're heated, the metal powders will burn.

When you try and react them with water, they react slowly, or they just don't react at all.

And they, but they are much more reactive with steam.

And they react less vigorously with halogens than Group 1, and they will form metal halides.

Let's have a quick check.

How do transition metals typically react with water? So I'll give you time to read those statements.

Well done if you said B, they react slowly or not at all.

Transition metals have lots of uses, and they're very widely used as catalysts in industrial processes.

And remember a catalyst is something that speeds up the rate of a reaction, but it doesn't actually take part itself.

And here we've got some uses of where transition metals are being used as catalysts.

Chromium is used in the production of polymers like polyethylene, which we use in packaging, and containers.

Manganese when we need to decompose hydrogen peroxide, and to oxidise alkenes.

Iron, in the Haber process.

Cobalt is used to convert hydrogen, and carbon monoxide into liquid fuels and waxes.

Nickel is used to hydrogenate oils to produce margarine.

And copper can be used to convert a mixture of hydrogen, carbon monoxide and carbon dioxide into methanol, which is a very useful chemical.

It can be used as a fuel in its own right in boilers, and cookers, and as a fuel for fuel cells, or buses, et cetera.

It can, it's also an important component in the production of paint and plastics too.

Let's have a quick check.

Transition metals are often used as catalysts in chemical reactions.

Is that true or is that false? Well done if you said that's true.

Can you justify your answer? Well done if you said B because lots of transition metals can be used as catalysts.

Well done.

I think we're ready for Task B now.

So Task B, Question 1.

Some reactions can be catalysed by multiple substances.

Hydrogen peroxide naturally decomposes into water and oxygen, but you're going to follow the method on the next slide.

You're going to record your observations in a suitable table.

You're testing four different catalysts.

And then you're going to rank your catalysts in order of effectiveness.

Be able to explain how you rank the catalysts, and suggest a change to the method to improve the accuracy.

So you might like to pause the video to take note of what you've got to do, and design your table, before you move on to the next slide with the method.

And here's the method.

So follow the instructions, carry out the experiment, and come back when you're ready.

So the first part of the task was to record your observations in a suitable table.

So this table is suitable.

You might have done something slightly different, but check you've got all the right components.

And then rank your catalysts in order of effectiveness.

Now again, you might have had different catalysts, so it might not be exactly the same.

So we used copper II oxide, iron III oxide, manganese IV oxide, and zinc II oxide.

But you might have had access to different metal oxide catalysts.

These were the observations seen.

So we looked at the number of bubbles being produced as the hydrogen peroxide was decomposing, and then we did the ranking.

So let's look at the answers to part C and D.

For part C, you had to explain how you ranked the catalysts.

And for D, you had to suggest a change.

So for C, the best catalyst was the one that produced the most bubbles of oxygen.

And the worst catalyst would be the one that produced the least bubbles.

In terms of improving the practical method, we could improve it by actually collecting the gas in a gas syringe, and then we could actually measure the volume of gas over a set time, say a minute or five minutes or so on.

And then we could actually make a calculation of the reaction rate.

So how did you do? And for Question 2 what I'd like you to do is write the formula for each of the following transition metal compounds, and give me the metal ion for each one.

So two parts there.

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

Okay, let's have a look at the results.

I've put it into a table, but you don't need to.

We know that the copper ion is Cu2+ due to the Roman numerals in brackets.

The sulphate ion has an overall charge of minus 2, so the formula is CuSO4 because the charges are equal and opposite, forming a neutral compound.

Nickel II nitrate.

So again, the Roman numeral two is used.

So we know that the nickel atom has lost two electrons, and formed a nickel ion, which has a charge of +2.

The overall charge of a nitrate ion is minus 1.

And when the ions combined form a neutral compound, the total negative and positive ions must balance.

So we need two nitrate ions for one nickel ion, and we put the nitrate in brackets, and a little subscript 2, which indicates two nitrate ions.

Chromium III oxide.

Chromium ions have a 3+ charge, and the oxide ions have a minus 2 charge.

So two chromium ions will balance out three oxide ions.

And so the formula is Cr2O3.

Manganese IV oxide.

So we know that the manganese ion has a +4 charge here.

And an oxide, as we've previously discussed, has a minus 2 charge.

So in order to form a neutral compound, two oxide ions are needed per manganese ion.

Absolutely amazing if you've got all those correct.

Well done, you are cracking this.

Let's have a look at Question 3.

The student has four compounds in front of them.

One is blue, one is green, and two is white.

Which compounds are likely to contain the transition metals? And can you suggest which metals might be involved? So pause the video, and come back when you're ready.

Let's have a look at the answers.

So we know transition metals are often coloured, and other metal compounds are usually white.

So the green compound could contain iron II ions, or chromium III ions.

And the blue compound could contain copper II ions.

So we've come to the end of the lesson today.

Let's have a look at the summary.

So we've learned that transition metals are generally stronger, harder, and more dense, and have higher melting points that Group 1 metals.

We know that transition metals react slowly with water, or they don't react with with it at all.

In order to get a reaction with some of them, we had to use steam.

Transition metals are often used as catalysts in industrial processes and they speed up chemical reactions but don't get involved.

And transition metals can form ions with different charges, and their compounds often exhibit beautiful, vibrant colours.

Well done and I look forward to working with you next lesson.