Hello and welcome to today's lesson.

We're going to be looking at transition metals today and we're gonna find out why they're so useful to our everyday life.

This is part of the unit: Industrial Chemistry.

So let's start the lesson.

Here is today's outcome.

So by the end of the lesson, you should be able to describe the physical and chemical properties of transition metals and some of their uses.

And we'll also compare them to the group one metals, the alkaline metals.

Here are the key words for today's lesson that I want you to listen out for, transition metal, catalyst, iron, and density.

And some of those words you should already have a good understanding what they mean, but here are these words written into a sentence.

You might like to pause the video here and make some notes for yourself to be able to refer back to throughout.

It's also useful to have a periodic table beside you.

And today's lesson is split into two parts.

We're going to look at the physical properties of transition metals and then the chemical properties of transition metals.

So let's get started.

So where do we find transition metals? We find them on the periodic table between groups two and three, this block here in the middle.

And you'll find metals that you probably know like copper and zinc and nickel and iron and gold and silver.

And then there'll be others that you've never heard of before.

So just have a quick look at the periodic table there and familiarise yourself with some of the symbols.

The transition metals, they're typical metals really.

So can you remember what the properties of them, the physical properties of metals were? Don't worry if not, I'll share.

So they're malleable, they're ductile, they're good conductors of heat and electricity.

They're shiny, they're sonorous, and they have high density and high melting and boiling points apart from mercury.

Find mercury on the periodic table.

Mercury has a melting point of minus 39 degrees centigrade, so it's a liquid at room temperature and that's unusual for a metal.

Let's just take a moment to remind ourselves what malleable and ductile and sonorous mean.

So malleable means that the metal can be bent or shaped without it shattering.

Ductile means that the metal can be pulled out into long wires without snapping or breaking.

And sonorous means when it's tapped or hit, it gives the sound like a ringing bell.

So those are all typical physical properties of metals that you will have come across before.

Now, some metals are magnetic.

Do you know which metals are magnetic? Not all metals are magnetic.

So iron is, cobalt is, and nickel.

These are magnetic and they're all transition metals.

While some of the transition metals exhibit magnetic properties, it's not universal.

Not all of the transition metals do this.

Some uses of these metals, because they are magnetic, include being generators, transformers, loudspeakers, permanent magnets, computer hard drives, and electric motors.

If we compare the transition metals to group one metals, your lithium, your sodium, potassium, they are generally stronger, harder and denser than group one metals and they have higher melting points.

So let me show you this in a table.

So you can see potassium there is a group one metal and the others are all transition metals.

And look at the differences between group one and the transition metals in terms of melting point, density, hardness, and tensile strength.

So there's quite a lot of difference there.

And due to these properties, transition metals are used a lot in construction and manufacturing.

So chromium is used in stainless steel for example.

Our taps are often plated in chromium as well.

Manganese, another transition metal, is used to improve the toughness of steel, and iron is used a lot in building materials and you can see in the image there lots of iron rods being used to give extra strength to the to the building materials.

And we often use cobalt in high strength alloys.

For example, on a jet engine, you need those to be pretty strong.

So cobalt is used there.

And nickel is used in coins and copper is used in electric wiring.

Let's do a quick check.

So which of the following statements about transition metals is true? I'll give you a moment.

Amazing if you said B, transition metals have higher melting points than group one metals with the exception of mercury.

Let's look at task A.

So we've got some students, four students, discussing transition metals.

Identify which statements are correct and update any of the incorrect statements.

So read all the statements there from the four students, decide which ones are correct, and then rewrite the other ones.

So pause the video and come back when you've completed the task.

Okay, are you ready for the answers? So Alex and Jacob are correct, transition metals are shiny, used in coins like copper and nickel, and transition metals are good conductors of heat and electricity.

Well done if you've identified those.

So let's have a look at Aisha's statement.

All transition metals are magnetic and we know that's not true.

Can you remember the three metals which are magnetic? Those were iron, nickel, and cobalt.

And Izzy said that transition metals were not used in construction because they were too soft.

Well that's not right.

So transition metals are used in construction due to their high strength and other useful properties.

Absolutely amazing if you've got those correct.

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

Transition metals can form ions with different charges and that's because their atoms can lose different numbers of electrons.

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

So here we've got a compound containing Fe2+ ions and it's that lovely green colour.

And here we've got a compound containing Fe3+ ions and it's a very different colour, orangy brown now.

And to help us, we use Roman numerals to represent these variable charges.

So iron with the II in brackets there refers to the iron 2+ ion and obviously the III in Roman numerals in the bracket there shows us that it's the Fe3+ ion.

Transition metals are known for their ability to form coloured compounds and solutions, and actually, a lot of paint and pigments contain transition metal compounds.

So here is the beautiful blue colour of Copper 2+ ions in a compound.

And actually, most other metals form white compounds, and when you dissolve them, they become colourless in solution.

So we've got an image there containing a compound with sodium plus ions, so it could be sodium chloride.

For example, table salt, it's white, if you were to put that into water, it would form a colourless solution.

Transition metal compounds that contain the same ion can actually have different colours depending on which other ions are present.

So copper is a really good example.

So we've just been looking at the lovely brilliant blue colour there that is present when copper two ions around and this is copper sulphate.

But look at this, this also contains copper 2+ ions and it's a black copper oxide.

Let's have a quick check.

So each transition metal can only form one ion, e.

g.

iron only forms Fe2+.

Is that true or is that false? Great job if you said false.

Can you justify your answer? Amazing if you said B, transition metals can form ions with different charges and their compounds often exhibit vibrant colours.

So we saw the copper 2+ copper sulphate without brilliant blue and then copper 2+ forming copper oxide, which was black.

Chemical formula for transition metal compounds will also vary due to the multiple ions that metals will form.

So we know that ion can form Fe2+ and Fe3+ ions and so we can have iron II chloride, iron II oxide, iron II nitrate.

So they all tell you that they're Fe2+ ions.

And then we've also got iron III chloride, iron III oxide, and iron III nitrate.

So you can see how important it is to have the Roman numerals in brackets here to help us understand which iron we're talking about.

Let's have a think about reactivity now.

So unlike our group one metals, transition metals react very slowly with water or they don't react at all, so group one metals like lithium or sodium or potassium.

Remember, in terms of their reaction with oxygen, remember that most of them are kept under oil so that they don't react with oxygen or water vapour.

So they react quite vigorously, especially when they're heated with oxygen.

Transition metals such as chromium, manganese, iron, cobalt, nickel, and copper there, they will form oxides with oxygen when they're heated.

They have to be heated.

So let's think about that reaction with water for the group one metals.

If you remember, you might have seen the video or actually seen it demonstrated where we put like a rice sized piece of lithium or sodium or potassium on the surface of the water and they scoot around the water producing a gas and that gas is hydrogen.

Can you remember how we test for hydrogen? Squeaky pop tests.

So a lighted splint will make the hydrogen gas explode and produce that squeaky pop.

And group one also produce hydroxides, which turn universe indicator blue or purple.

Now if we think about transition metals, they pretty much don't react or it's really, really slow with water, you can put them all in water.

Think about putting an iron nail in water.

It will tell a piece of copper, it's not going to react or it's going to take a long time for it to react.

They are slightly more reactive if you place them in steam there.

Let's think about the reactions with group seven.

So we remember our group one and group seven react quite well together.

They react vigorously and produce metal halides.

The transition metals react less vigorously but will form metal halides.

Let's have a quick check.

So how do transition metals typically react with water? Well done if you said part B, they react slowly or not at all.

Now another use of transition metals is as a catalyst in industrial processes.

Remember a catalyst is something that speeds up the rate of a reaction without being used up itself.

So if we look at all these metals, they all can act as catalysts.

So chromium is involved in the production of polymers such as polyethylene, which is used in packaging and containers.

Manganese is a catalyst for the decomposition of hydrogen peroxide and also for the oxidation of alkenes.

Iron that is used as a catalyst to convert nitrogen and hydrogen into ammonia.

You might know that as the Haber process.

Cobalt will convert a mixture of hydrogen and carbon monoxide into liquid fuels and waxes.

Nickel is used in the production of margarine and copper is a catalyst for the conversion of hydrogen, carbon monoxide, and carbon dioxide into a compound called methanol.

And methanol is also used as a fuel.

Let's have a quick check.

So true or false, transition metals are often used as catalysts in chemical reactions.

Great job if you said A.

And can you justify your answer? Which one of these would you use? Amazing job if you said B, many transition metals are used as catalysts.

Not just iron, copper, chromium, and nickel.

Many of them.

Remember that catalysts are used in many industrial processes more than we've mentioned today.

And the reason that that so important is that they reduce the energy and time needed for reactions.

And so in industry that helps to reduce the costs and it can also help to reduce the impact on the environment too.

So I think we're ready for task B.

Some reactions can be catalysed by multiple substances.

Hydrogen peroxide naturally decomposes into water and oxygen.

The rate of this reaction can be improved by using a catalyst.

So a method is provided on the next slide for you.

I want you to record your observations in a suitable table.

I want you to rank the four catalysts that you're going to test in order of effectiveness, which ones were the, you know, which was the most effective, which was the least effective.

And I want you to explain how you carried out your ranking and then suggest a change to the method on the slide to improve accuracy.

So here's the method slide.

Prepare four tubes with five centimetre cubes of peroxide.

Add about one quarter of a spatula measure of the first muscle oxide that you're going to test to test tube a.

Watch and record your observations and then repeat for the three other metal oxides that you're going to use as catalysts.

So think about the table that you're going to use to record your observations.

And then you're going to rank them in order of effectiveness as a catalyst.

And then you've got to explain how you decided on that ranking.

And then finally, have a look at this method and decide what you would change to improve the accuracy.

So pause the video and come back when you've had chance to carry out your tests and complete your table.

Hello, welcome back.

Let's have a look.

So here's my table.

Yours might be slightly different and here's my observations as well.

So I use copper, iron, manganese and zinc oxides.

You might have used different oxides.

Let's have a look at the observations that we saw.

So a small number of bubbles produced quite slowly by copper.

Iron was a sort of moderate number of bubbles that produced a steady rate.

Manganese produced a large number of bubbles very quickly.

And zinc, the reaction was really slow.

We hardly saw any bubbles produced.

I wonder if you got similar results.

So I've then ranked them there.

Wonderful.

So let's have a look at part C, which was explain how you ranked the catalyst in order of effectiveness.

So I decided the best catalyst was the one that produced the most bubbles of oxygen and the worst catalyst produced the least bubbles.

For part D, changed the method to improve accuracy.

You might have said different, but I thought one way that the practical could be improved was to actually collect the gas in a gas syringe and measure the volume of gas that we collected during a set time and then we could calculate the reaction rate.

What did you put? You might have chosen to actually find the mass of the metal oxide rather than using a spatula.

That would also be good.

Let's have a look at question two now.

So write the formula for the following transition metal compounds giving the metal iron in each.

So copper II sulphate, nickel II nitrate, chromium III oxide and manganese IV oxide.

And then question three, assume has four compounds in front of them, one blue, one green, two white.

Which compounds are likely to contain transition metals? Can you suggest which metals they might contain? So pause the video and come back when you've done those two questions.

Welcome back.

Let's have a look.

So here are the formula.

We know that the copper iron is CU2+ due to the Roman numerals.

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

Nickel 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 with a charge of plus two.

The overall charge of a nitrate ion, NO3, is minus one.

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

So we need two nitrate ions to balance out the nickel ion.

So we put a bracket around the nitrate and a little subscript two to show that there's two nitrate ions there.

Chromium oxide, chromium ions have a three plus charge, which we can tell from their Roman numerals and oxide ions have a two minus charge.

So two chromium ions will balance out three oxide ions giving us the formula Cr2O3.

We know that the manganese ion has a plus four charge and an oxide ion has a minus two charge.

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

Amazing if you've got all those correct.

Well done, not easy.

And let's look at question three now.

So we've got to decide which compounds are likely to contain transition metals and then we've got to suggest which metals might be involved.

Remember, transition metal compounds tend to be coloured and other metal compounds tend to be white.

So we would suggest that the blue and the green compounds are likely to contain transition metals.

The green compound could be Fe2+ and the blue could contain copper 2+ ions.

Amazing if you got those right as well.

Well done.

So we've come to the end of our lesson now, let's have a quick look at the summary of our learning today.

So transition metals are generally stronger, harder, more dense, and have higher melting points than group one metals.

Apart from, can you remember which one? Mercury.

That's right.

Remember.

Because that had a melting point of minus 39 degrees centigrade, which means it would be a liquid at room temperature transition metals react really slowly with water or they don't react at all.

If you want to react to transition metal with water, then you might need to use steam.

Transition metals are often catalysts and that means they speed up reactions without taking part in the reaction themselves and they're really important in lots of industrial processes.

And then transition metals conform ion with different charges.

We've just been talking about Fe2+ and Fe3+.

And their compounds can often exhibit these beautiful vibrant colours.

So copper two plus iron, if you remember, is that in copper sulphate is that bright blue colour and that's why transition metal compounds are often used in paint pigments, for example.

So well done.

Absolutely amazing.

I hope you feel a lot more confident now about the properties, chemical and physical, of transition metals that you could compare them to group one metals and that you know some of the uses of transition metals and how important they're to our lives today.

Well done and I'll see you next time.