Lesson video

Hello, I am Mrs. Adcock and welcome to today's lesson.

Today's lesson is on developing a reactivity series for metals.

We are going to be looking at how we can use experimental data to develop a reactivity series for metals.

Today's lesson outcome is, I can compare the reactions of different metals with water and dilute acids in order to work out the reactivity series for metals.

Some of the keywords we will be using in today's lesson include ion, salt, reactivity series, and displacement.

Here you can see each of those keywords written in a sentence.

It would be a good idea to pause the video now and read through those sentences.

You might like to make some notes so that you can refer back to them later in the lesson if needed.

Today's lesson on developing a reactivity series for metals is split into three main parts.

First of all, we are going to be looking at reactions of metals.

Then we're going to move on to look at the reactivity series, and then we will finish today's lesson by looking at displacement reactions.

Let's get started on reactions of metals.

Some metals react with acids to produce a salt and hydrogen gas.

Just a reminder that a salt is an ionic compound that's made up of positive and negative ions that are electrostatically attracted to each other.

So when metals react with acids, they produce a salt and hydrogen gas.

Here we can see the general word equation.

We have a metal reacting with an acid and that will produce a salt and hydrogen gas.

And now we've got an example of a metal and an acid reacting together.

Our metal is magnesium and we can react to that with the acid, sulfuric acid and then these will react together to produce a salt, and in this example our salt is magnesium sulphate and then we form hydrogen gas.

At the bottom we have a balanced symbol equation for this reaction.

The magnesium is reacting with sulfuric acid and we can see how the magnesium and the sulphate parts of the acid come together to form our salt, we are left with hydrogen atoms, which form our hydrogen gas.

What other products, when a metal and acid react together? Do we form A, a metal hydroxide, B, a salt, C, hydrogen, or D water? The correct answers are B, salt, and C, hydrogen.

Well done if you selected B and C.

Some metals will react with acid and when they do, they will form a salt and hydrogen.

We produce different salts depending on the metal and the acid that we react together.

In the table we can see the salt that will be produced depending on the acid that is used.

If we use hydrochloric acid, then the salt that is produced will be a metal chloride.

So for example, if we reacted sodium with hydrochloric acid, we would make sodium chloride.

If we use nitric acid, then the salt will end in nitrate, so we will make a metal nitrate.

That will be the name of our salt if we use nitric acid.

If we use sulfuric acid and react this with a metal, then the salt name will be metal sulphate.

For example, if we reacted aluminium with sulfuric acid, we would make aluminium sulphate.

In the table you can also see the molecular formula of each of those acids.

These are useful because we can see that each of our acids contains hydrogen, so we will form hydrogen as one of our products and then the metal will react with the chloride atoms in hydrochloric acid or that nitrate group in nitric acid or the sulphate group in sulfuric acid.

In a salt, the hydrogen ions from the acid have been replaced with metal ions.

If we look at sulfuric acid, we can see it has the molecular formula H2SO4.

When we react this with a metal, the hydrogen ions will be replaced with metal ions and we will produce a metal sulphate plus hydrogen gas.

We are going to use this question to help us practise naming our salts.

I will have a go and then it'll be your turn to have a go.

Name the products when magnesium reacts with hydrochloric acid.

When a metal such as magnesium reacts with an acid such as hydrochloric acid, the products will be a salt and hydrogen gas.

The salt name will start with the metal used.

In this question, the metal used was magnesium, so our salt name will start with magnesium.

The salt will end in chloride because we used hydrochloric acid.

Hopefully you can remember from the previous slide, if we use hydrochloric acid, our salt will end in chloride.

If we use nitric acid, our salt will end in nitrate and if we use sulfuric acid, our salt will end in sulphate.

We used hydrochloric acid in this question, so therefore our salt will end with chloride.

The products are therefore magnesium chloride, that's our salt, plus hydrogen.

Your turn to have a go.

Name the products when calcium reacts with sulfuric acid.

Pause the video now and have a go at answering this question.

We have a metal and an acid reacting together.

Our metal is calcium and our acid is sulfuric acid.

When a metal and acid react together, the products will be a salt and hydrogen gas.

The salt name will start with the metal used.

In this question, the metal is calcium and the salt will end in sulphate because we used sulfuric acid.

Therefore, the products when calcium reacts with sulfuric acid are calcium sulphate, that's the name of the salt, plus hydrogen.

Well done if you are able to name both of those products.

Time for another check for understanding.

Name the salt produced when zinc reacts with nitric acid.

Do zinc and nitric acid react together to make A, zinc chloride, B, zinc nitrate, C, nitrogen oxide, D, hydrogen.

And remember, you are naming the salt that is produced.

The correct answer is B, zinc nitrate.

The metal was zinc and the acid used was nitric acid, so the salt produced will be zinc nitrate.

Well done if you chose B, zinc nitrate.

Some metals will react with water and when they react with water, they will produce a metal hydroxide and hydrogen gas.

Here we can see the general word equation for when a metal reacts with water.

When a metal reacts with water, they'll react together and we produce metal hydroxide plus hydrogen.

We can look at an example here of a metal reacting with water.

We've got sodium.

Sodium is in group one.

Group one metals will react with water.

They are very reactive metals.

Sodium and water react together to produce sodium hydroxide plus hydrogen.

Here we can see a balanced symbol equation for this reaction, we have 2Na.

They react with two H2O molecules to produce 2NaOH molecules plus one molecule of H2.

Let's see if you can remember what we just learnt.

What are the products when a group one metal reacts with cold water? Will it produce A, a salt plus hydrogen, B, salt plus water, C, metal hydroxide and hydrogen, or D, metal hydroxide and water? The correct answer is C, a metal hydroxide plus hydrogen.

So well done if you chose option C.

When a metal reacts with water, we produce a metal hydroxide and hydrogen.

When potassium reacts with water, what will the product or products be? Will we produce A, potassium chloride, B, potassium nitrate, C, potassium hydroxide, or D, hydrogen? When potassium reacts with water, we will produce a metal hydroxide.

In this example, our metal hydroxide will be potassium hydroxide and we will also produce hydrogen.

Well done if you identified potassium hydroxide and hydrogen as the products when potassium reacts with water.

Time for our first practise task of today's lesson.

For this question you need to complete the following word equations.

We've got reactions there where metals react with water and metals react with acids.

Think carefully about what the products might be or what the reactants will be if you've been given the products in those word equations.

Pause the video now have a go at answering those questions.

Come back when you're ready to go over the answers.

Right, let's see how you got on.

Lithium is a group one metal and that will react with water and when they react, we will form a metal hydroxide.

In this example that will be lithium hydroxide and we also produce hydrogen.

B, we've got something that's going to react with water to form calcium hydroxide.

There's a clue there in that product, our metal hydroxide is calcium hydroxide, so we must have reacted calcium with water to form calcium hydroxide plus hydrogen.

In C, we've got magnesium and nitric acid.

A metal and acid will react together to make a salt and hydrogen.

Our salt will be magnesium nitrate plus hydrogen.

And in D, our salt will be aluminium because that's the name of our metal.

And then from the sulfuric acid we get the sulphate parts, so we will form aluminium sulphate and don't forget the hydrogen gas as well, which will be our other product.

In E, we've got sodium and it's reacting with an unknown acid and we produced the salt sodium chloride.

Now because our salt ends in chloride, that gives us a clue to the acid that was used.

So sodium must react with hydrochloric acid to produce the salt, sodium chloride and hydrogen gas.

In F, we don't know either of our reactants, but we do know the products are zinc sulphate and hydrogen, therefore the metal must be zinc and the acid that's been used is sulfuric acid.

Well done if you correctly identified those missing reactants and products for those questions.

We have had a look at how some metals react with water and how some metals react with acids and the products that are produced when these reactions take place.

We are now going to move on to have a look at the reactivity series.

We can order metals from most reactive to least reactive by observing how different metals react with water and acid.

Here are some results from reacting different metals with water.

We've got potassium and when we reacted potassium with water, we observed that there was a reaction that took place and bubbles of hydrogen gas are formed.

When zinc was added to water, the observation was that there was no reaction.

Do you think based on this data that potassium or zinc is more reactive? Hopefully you identified that potassium is more reactive than zinc because the potassium reacted with water, but the zinc did not react with water.

Earlier we said that only some metals react with water.

It is only metals that are highly reactive, such as those in group one and group two that react with cold water.

Here we can see in this reaction potassium, which is in group one is reacting with water, and when potassium reacts with water, it produces potassium hydroxide and hydrogen.

Here we can see acid that has been added to the metals, magnesium, iron, zinc and copper.

We can see the magnesium reacts vigorously and it's producing lots of bubbles of hydrogen gas there.

Iron produces lots of bubbles but is not reacting as vigorously as the magnesium with the acid.

The zinc is producing fewer bubbles and the copper does not react with the acid.

We can use these observations to help us think about which is the most and which is the least reactive metal.

Which metal do you think is the most reactive between magnesium, iron, zinc and copper, and which metal do you think is the least reactive? Hopefully you identified that magnesium is the most reactive.

The magnesium reacted vigorously with the acid.

The least reactive is copper, and we didn't see any reaction between the copper and the acid.

Time for check for understanding.

Metal A, B and C are added to water and they're added to acid.

Metal A reacts with the water and acid.

Metal B reacts only with the acid and metal C does not react.

Which metal is the most reactive? Is it metal A, metal B, or metal C? The correct answer is metal A.

Metal A is the most reactive and we know this because it was the only metal that reacted both with water and acid.

Here we have a results table showing us a list of different metals and their reactions with water and the reaction with acid.

If we look at the top, we can see that potassium and sodium reacted with water and they reacted violently with acid.

The calcium and magnesium, they also reacted with water and they reacted with the acid, although not so violently.

The aluminium did not react with water, but it did react with acid.

The zinc and iron did not react with water and they reacted slowly with acid and the copper did not react with water and it also did not react with the acid.

We can use this experimental data to help us place metals in order of reactivity.

The more reactive metals are at the top and the less reactive metals are at the bottom.

Here we can see that list of metals with the more reactive metal at the top and the less reactive metals at the bottom.

So the reactivity decreases as we go from the top down to the bottom.

This ordering of metals based on their reactivity is known as the reactivity series.

So the reactivity series has the more reactive metals at the top and the less reactive metals at the bottom, so reactivity decreases down the reactivity series.

The non-metals, carbon and hydrogen are often included in the reactivity series for reference, and we can see the position of carbon and hydrogen on our reactivity series there.

Which is the most reactive metal on this reactivity series? Is it A, potassium B, carbon or C, gold? Think about where we place the more reactive metals on the reactivity series to help you work out the answer.

The correct answer is A, potassium.

Potassium is the most reactive metal on that reactivity series because it's the metal at the top of that reactivity series.

Which two non-metals are often placed for reference in the reactivity series? Is it A, potassium B, carbon, C, gold, or D, hydrogen? Remember, you're looking for two non-metals that are often placed in the reactivity series.

The correct answers are carbon and hydrogen.

So well done if you selected carbon and hydrogen.

Metals have different reactivities based on their tendency to lose electrons and form positive ions.

Remember that ions are atoms or group of atoms that have a positive or negative charge due to the loss or gain of electrons.

Metals lose electrons to form positive ions and the more easily a metal atom loses electrons to form a positive ion, the more reactive it is.

Group one metals such as potassium and sodium, which are at the top of our reactivity series, they easily lose electrons to form positive ions and therefore they are very reactive.

We can see potassium and sodium positioned at the top of our reactivity series.

Gold is an unreactive metal because it does not tend to lose electrons to form ions.

Gold is positioned at the bottom of our reactivity series.

Time for a check for understanding.

Highly reactive metals tend to lose electrons more easily to form negative ions.

Is that statement true or false? That statement is false.

Can you justify your answer? Unreactive metals tend to lose electrons easily to form negative ions, or highly reactive metals tend to lose electrons easily to form positive ions.

The correct answer is B.

So well done if you identified that highly reactive metals tend to lose electrons easily to form positive ions.

Time for another practise task.

You've got two questions to answer here.

Question one, four metals A, B, C, and D were added to sulfuric acid.

You can see in the image you've got four test tubes containing sulfuric acid, and to those the metals A, B, C, and D have been added.

You need to one A, order the metals into order of reactivity starting with the most reactive.

B, one of the metals is gold, which metal is gold? Give a reason for your answer.

Question two, you need to explain in terms of how easily they form ions why sodium is more reactive than iron.

Pause the video now have a go at answering those questions.

Then when you come back, we'll go over the answers.

Question one A, order the metals into order of reactivity starting with the most reactive.

You should have had the order A, D, B, then C.

We know A is the most reactive because there are lots of bubbles formed when A reacts with the acid.

Then D has fewer bubbles and B has even fewer bubbles again, and C does not appear to have reacted with the acid.

One of the metals is gold, which metal is gold? Give a reason for your answer.

Metal C is gold.

It is an unreactive metal that does not react with acid.

Well done if you identified metal C as gold.

You must have remembered that gold is an unreactive metal and noticed that C has not reacted with the acid.

Question two, explain in terms of how easily they form ions why sodium is more reactive than iron.

Sodium is more reactive than iron because sodium more easily loses electrons to form positive ions than iron.

That's great work if you got that question correct.

We have looked at reactions of metals and we have looked at the reactivity series.

Now we are going to move on to look at displacement reactions.

We can use the reactivity series to predict the products of a reaction.

A more reactive metal will replace a less reactive metal in a compound in a displacement reaction.

For example, we've got magnesium here and it's reacting with copper sulphate.

Now we can use the reactivity series to identify that magnesium is more reactive than copper, so replaces it in the compound.

If a less reactive metal is added to a metal compound containing a more reactive metal, then no reaction will occur.

For example, we have aluminium oxide as our compound and we are adding copper.

Copper is less reactive than aluminium.

Copper cannot displace aluminium in the aluminium oxide compound, therefore, no reaction occurs.

Displacement reactions occur when A, metals are listed in order of reactivity.

B, a more reactive metal takes the place of a less reactive metal in a compound, or C, a less reactive metal takes the place of a more reactive metal in a compound.

The correct answer is B.

Well done if you identified that a displacement reaction occurs when a more reactive metal takes the place of a less reactive metal in a compound.

Time for our final practise task of today's lesson.

For this question, you need to use the reactivity series to work out the products for the following reactions.

If the reaction will not take place, then just write no reaction.

We have zinc reacting with copper sulphate, iron oxide and aluminium, iron and magnesium chloride, calcium nitrate plus sodium, gold plus zinc sulphate, and magnesium plus aluminium oxide.

Use the reactivity series you've been given there to help you identify which is the most reactive metal and remember, a reaction will only occur if a more reactive metal can take the place of a less reactive metal in a compound.

Pause the video now, have a go at answering this question and then we'll go over the answers when you come back.

Hopefully you were able to answer these questions.

Let's just go through the answers.

One A, zinc is more reactive than copper, so zinc will displace the copper and we will form zinc sulphate plus copper.

Aluminium is more reactive than iron, so the aluminium will displace the iron and we will produce aluminium oxide plus iron.

In C, iron is less reactive than magnesium, so the iron cannot displace the magnesium from the compound.

Therefore, no reaction occurs in C.

In D, sodium is more reactive than calcium, therefore the sodium will displace the calcium and we form sodium nitrate plus calcium.

In E, gold is less reactive than zinc.

Therefore, the gold cannot displace the zinc in the zinc sulphate and therefore no reaction occurs there.

F, sodium is more reactive than aluminium, therefore the sodium will displace the aluminium from that compound and we will produce sodium oxide plus aluminium.

Hopefully you got lots of those correct.

Well done if you did get them correct.

We have reached the end of today's lesson on developing a reactivity series for metals.

Let's just summarise some of the key points that we've covered in today's lesson.

A more reactive element will replace a less reactive element in a compound, and this is known as a displacement reaction.

The more easily a metal atom loses electrons and forms a positive ion, then the more reactive it is.

Some metals react with acid and when they do, they produce a metal salt and hydrogen gas.

Some metals react with water and when they react, they produce a metal hydroxide and hydrogen gas.

Carbon and hydrogen are non-metals that are often included in the reactivity series and carbon is a non-metal element, often included in the reactivity series between aluminium and zinc.

You've worked really hard in today's lesson, so well done.

I've enjoyed the lesson.

I hope you have too and I hope you're able to join me for another lesson soon.