Lesson video

Welcome to today's lesson on properties of elements.

It's part of the unit Atoms, elements, and compounds.

My name is Mrs. Mytum-Smithson and today we're going to learn about the chemical and physical properties of elements.

We're going to go through this lesson step by step, so don't worry if at this stage you don't know too much about elements.

By the end of the lesson you should be able to describe the chemical and physical properties of different chemical elements.

Here are today's keywords: pure substance, property, physical property, chemical property.

On the next slide, there's some sentences that include these key keywords, so feel free to pause the video and read the keyword sentences.

Then press play when you're ready for the rest of the lesson.

Today's lesson on properties of elements consists of two learning cycles.

physical properties of elements, and then we're going to move on and learn about chemical properties and trends of elements.

The first learning cycle is physical properties of elements, so let's get learning.

Here's a picture of an element.

It's a pure gold nugget.

Some lucky person has found this in the ground.

It's a pure substance and it's made up of only one type of atom.

So if we were to zoom in on this, we would see that it's only made up of gold atoms. So if you have a look there, you can see these gold atoms which are represented by these grey circles.

When many atoms of the same type join together, they create the element's overall characteristics.

That's their overall properties, the way that they behave.

So if the bricks represented atoms, the brick wall would represent an element because atoms are the basic building blocks of elements.

They don't share the same properties as the whole element.

For example, a common misunderstanding IS that atoms are actually coloured.

So lots of people think that gold atoms, if you zoomed in and saw a gold atom, it would be gold colour.

In fact, all individual atoms are colourless.

They have no colour.

So if I zoomed in on some copper and I got one single atom, it would not be copper coloured, it would be colourless.

I've got a quick check for understanding for you.

True or false? Individual silver atoms are coloured silver.

Pause the video for some thinking time.

Press play when you're ready for the answer, well done If you said False.

Now you're going to choose one of these statements to justify your answer.

Silver atoms don't have the same properties as the element silver.

Individual atoms have no colour.

Individual silver atoms are only coloured silver when in the solid state.

Pause for some thinking time and press play when you've got your answer.

Well done if you said silver atoms don't have the same properties as the element silver.

Individual atoms have no colour.

Usually we call this colourless, meaning has no colour.

Well done if you got that one right.

Aluminium and chlorine are elements, What I'd like you to do now is select all the answers that describe elements.

Aluminium is made of one type of atom.

Chlorine is made up of one type of atom.

Aluminium is made up of two different atoms. Chlorine is made of three types of atoms. Pause the video now and press play when you've got your answer.

Well done if you said, A, aluminium is made of one type of atom and chlorine is made up of one type of atom.

So aluminium and chlorine are elements and elements are made up of just one type of atom.

Well done if you got that one right.

All elements have a fixed melting and boiling point.

So melting and boiling points are physical properties, and what we mean by fixed melting and boiling point is it melts at a single temperature.

So for example, gold would turn from the solid state to the liquid state at 1,064 degrees C.

Its boiling point is much higher at 2,836 degrees C, but it is still a single number.

So it's a fixed boiling point and a fixed melting point.

If we have a look at mercury, which is an interesting element, it's liquid at room temperature.

So that's got a melting point of -39 degrees C and it would boil at 357 degrees C.

And our final example is bromine.

So it's got a melting point of -7 degrees C and it's got a boiling point of 59 degrees C.

So you can see that that is an element because it has a fixed melting and boiling point, a single number.

Let's have a check for understanding now.

A substance has a melting point of 75 to 80 degrees C.

This means that it is an element.

Is that true or is that false? Pause the video for some thinking time and press play when you've got your answer.

Well done if you said false.

That statement is incorrect.

Now I want you to justify your answer.

So you've got two choices: all elements have fixed melting points and fixed boiling points, or all substances that are elements have a temperature range for melting and boiling.

Which one of those do you think is correct? Pause the video for some thinking time.

Press play when you've got your answer.

Well done if you said A, all elements do have a fixed melting point and a fixed boiling point.

That means that you will get a single number for melting and a single number for boiling, not a range.

So well done if you got that one correct.

Physical properties describe how the element appears and behaves.

So the state of matter, usually we'll talk about the state of matter at room temperature.

So for helium, which is an element, these balloons are filled with helium gas, and that is a gas at room temperature.

Is the element strong or is it weak? That's another physical property.

Thermal conductivity, it sounds quite a difficult word, sounds quite long, but it just tells you can it conduct heat or not conduct heat.

This pan is made of iron.

If you put it on a stove, it will conduct heat from the flame to the food that it's cooking.

So that element there has got thermal conductivity or good thermal conductivity.

Appearance, so what something looks like.

Is it shiny like gold, all polished up, or is it dull? Here's some more properties: So we've got ductile, this is a special word that means it can be pulled into wires.

So ductile, it can be pulled into wires.

This is copper.

Copper is a metal that is ductile.

That means that you can pull it into wires.

Malleable, so malleable means it can be bent into a shape without breaking when a force is applied.

So this is really useful if you want to make something into a particular shape.

You can bend it and it won't break.

That means that that element is malleable.

Electrical conductivity.

So again, that conductivity just means can it conduct? In this case we're looking at electrical conductivity.

So can it conduct electricity or not? These copper wires here can conduct electricity.

Here's some physical properties of aluminium.

So aluminium has got a fixed melting point at 660 degrees C.

So we know it's an element.

It's got good thermal and electrical conductivity, which means it can take heat from one place to another.

So this is really good if you make a pan out of aluminium, it can take heat from the stove, take it to the food, pass it onto the food, and if you made a wire from aluminium, it could conduct electricity.

So it will carry a charge through that wire.

So that's really good.

It's soft compared to other metal elements.

So it would dent quite easily.

If you hit it with something like a hammer, it would dent.

It's malleable, which means that we can bend it into the shape of what we want to make it from.

So maybe we want to make a bowl from it or make a pan from it.

It will take that shape on without breaking.

It's ductile, which means we can pull it into wires.

So that might be quite useful for us if we want it in a wire shape or we need to use it as a wire, that's useful.

And finally it's shiny.

So you can see here from the image that aluminium is shiny.

That's another physical property.

Let's have a look at some physical properties of another element, here's bromine.

It's got a low boiling point of 59 degrees C.

It doesn't take a lot of energy to heat this up and make it from a liquid to a gas state.

It's dull orange.

So remember, colour is an example of a physical property.

It's liquid at room temperature.

It's quite an unusual element for that.

There's only two elements that are liquid at room temperature, one's mercury and the other one's bromine.

So that's a fun fact that you can share with everybody you know.

It's got an unpleasant smell, though, so you wouldn't wanna go sniffing this.

So let's have a quick check now.

True or false, the physical properties of aluminium are that it is shiny, malleable, and liquid at room temperature.

Is that true or is that false? Pause the video for some thinking time.

Press play when you've got your answer.

Well done it if you said that that is false.

Now I want you to justify your answer.

Some physical properties of aluminium are that it is shiny, ductile, and liquid at room temperature.

Some physical properties of aluminium are that it is shiny, malleable, and solid at room temperature.

So pause the video for some thinking time.

Press play when you've got your answer.

Well done if you said some physical properties of aluminium are that it is shiny, malleable, and solid at room temperature.

You can see there, there's some foil.

It's scrunched up into a ball.

It's definitely a solid at room temperature.

So remember, state of matter is one of the physical properties of an element.

Izzy and Alex have been discussing elements.

They've got some statements and I want you to select the correct option from the brackets.

So here's Izzy's first statement.

"An element has a fixed, a range of, or no melting point or points.

And an element has a fixed, a range of, or no boiling points." Alex's sentence now: "An element is always, sometimes, never made of only one type of atom." Pause the video, complete the task, press play when you want to go through the answers.

Well done for completing that part of the task.

Let's go through the answers.

An element has got a fixed melting point and it's also got a fixed boiling point.

If it was a range, it would not be an element.

So it's a fixed melting point and a fixed boiling point.

Alex has said an element is always made up of only one type of atom.

That's actually what makes an element.

So if it's only got one type of atom, it is an element.

Well done if you've got those statements correct.

I'd like you now to correct some more statements from Izzy and Alex.

So Izzy's now talking about atoms of elements.

So she said, "Atoms of an element are the same colour, are different colours, have no colour.

For example, copper atoms are a copper colour, colourless, which means they've got no colour, a silver metal colour." Alex has said, "A single atom of the element has the same or different properties to a larger quantity of the element." Pause the video for some thinking time.

Press play when you've got your answer.

Well done for completing that task.

Izzy said, "Atoms of an element have no colour." So well done for that one.

For example, copper elements are colourless.

That means that they've got no colour, they're not a copper colour.

Only if you've got lots of those atoms joined together, do they become a copper colour.

So Alex said, "A single atom of an element has different properties to a larger quantity of that element." Well done if you've got all that correct.

So now we're going to go onto part two of Task A.

For this, I want you to identify the substances which are elements and which are not elements.

So you've got substances A to F, you've got some melting points and some boiling points, and then we've got the number of types of atom in a substance.

What you're going to do is you're gonna have a look at the melting point, the boiling point, and the number of types of atom in the substance.

And you are going to write in that final column is an element or not an element.

So pause the video now for some thinking time, complete this task, and then press play when you've got your answers.

Well done for working really hard.

Now let's go through the answers.

So we'll have a look at substance A to start with.

So it's got a fixed melting point at 98 and a fixed boiling point at 150 and it's got one type of atom.

So hopefully you've managed to identify that that is an element.

Then we'll have a look at B.

So B has got fixed melting point at zero, boiling point at 100, but because it's got two types of atom in the substance that makes it not an element.

Then we're gonna have a look at C.

C's got a melting point of between 15 and 17 and it's got a boiling point between 80 and 85.

It's got six types of atoms in the substance.

So that makes that that is not an element.

We're gonna have a look now at D.

So D has got 32 for its melting point, 65 for its boiling point.

It's got two different types of atom in the substance.

So that means it's going to be not an element.

For E, -290, -185 for the boiling point and one type of atom in the substance.

That means that that is an element.

I'm gonna have a look at F now.

So because it's got this melting point range and a boiling point range, that means that it's not an element, and to confirm that, it's got five different types of atom in that substance, which definitely makes it not an element.

Well done for completing that task.

I hope you managed to get lots and lots of those right.

Let's have a look now at part three of Task A.

This is coal, it's made of carbon.

Select the properties of carbon from the list.

So carbon's an element.

What I want you to do is select which ones of these properties does carbon have: ductile or not ductile, shiny or dull, brittle or malleable, and the state of matter at room temperature.

Pause the video now.

Press play when you've done your work.

Well done for completing that task.

Let's have a look at the properties.

It's not ductile.

We can't pull carbon or coal into wires.

It's dull.

You can see that just by looking at the picture.

It's definitely dull, and it's brittle.

If you hit it with a hammer, it breaks up really easily.

And it is a solid at room temperature.

So well done if you've got those four answers correct.

Here's part four of Task A.

What I want you to do now is this wiring is made of copper.

List the properties of copper and explain how you know that copper has got this property.

So here's the list of properties to choose from: Ductile or not ductile, shiny or dull, not an electrical conductor or electrical conductor, strong or weak, malleable or brittle, and the state of matter at room temperature.

Pause the video now, complete the task, and then press play and we'll go through the answers.

How'd you get on with that task? I hope you did okay.

Let's go through the answers and see how well you've done.

So here's the list of properties of copper: ductile, shiny, electrical conductor, malleable, strong and solid.

And how do we know that they've got these properties? So ductile, that picture is showing wires, so it's been pulled into a wire, so long and thin.

That means that it's ductile.

The picture shows that it's shiny, so we can see that it's shiny, it's reflecting the light.

So if you are reflecting the light or you can see it's shiny, that's absolutely fine.

Electrical conductor, you can see actually that the picture shows that it's electrical wires so we know that it conducts electricity.

So well done if you got that bit.

It's malleable, and you know that because you can bend those wires made of copper into shape without breaking.

It's strong which means it's difficult to break.

So you wouldn't just go up to that wire, bend it and it would snap, it is strong.

And it is solid at room temperature.

So well done if you've got all of those correct.

Well done for working hard through the physical properties of elements learning cycle.

Now we're going to move on to the chemical properties and trends of elements.

Let's get going.

Each element has specific chemical properties.

So in the first learning cycle we looked at physical properties and we know that they are unique to each element.

And this is same with chemical properties.

Each chemical property is how the substance reacts with a specific chemical.

So that's what a chemical property is.

So we're going to look at how each element reacts with water, acids, or oxygen.

New substances are always formed.

So this is the difference between physical properties and chemical properties.

So physical properties, you don't get new substances, but chemical properties you do.

So here's our example here.

So one of the chemical properties of iron is that it reacts slowly with oxygen to form a new substance called iron oxide.

We know this is rust.

We've probably seen this around quite a lot.

So this is when iron reacts slowly with oxygen to form iron oxide.

True or false? An example of a chemical property is that the element hydrogen reacts explosively with oxygen and a new product is made.

Is that true or is that false? Pause the video for some thinking time.

Press play when you've got your answer.

Well done if you said that that was true.

You got that one right.

Now I want you to justify your answer.

Hydrogen reacting explosively with oxygen is a chemical property of hydrogen.

Hydrogen reacting to make a new product is an example of a physical property.

Pause the video for some thinking time and press play when you've got your answer.

Well done if you said, A, hydrogen reacting explosively with oxygen is a chemical property of hydrogen.

So here's an example of a chemical property.

These elements all react vigorously with water.

Lithium at the top is the least reactive, going all the way down to rubidium and cesium which are very, very, very reactive.

So here's a physical property.

These elements are all soft, some elements are softer than others.

So lithium is the hardest, but it's still soft.

As you go down the list, the elements get softer.

So they are similar, not identical to each other.

Now we're gonna have a look at these.

So these elements are not very reactive, and these have got low melting and boiling points.

They don't have the same melting and boiling points, but they all have similar low melting and boiling points.

True or false? Elements in the same part of the periodic table behave identically to each other.

Is that true or is that false? Pause the video for some thinking time.

Press play when you've got your answer.

Well done if you said false, that is indeed false.

Now I want you to justify your answer.

Is it that elements have similar chemical and physical properties are near each other in the periodic table, or elements are arranged by date of their discovery on the periodic table? Pause the video for some thinking time.

Press play when you've got your answer.

Well done if you said elements that have got similar chemical and physical properties are near each other in the periodic table.

For this task, I've got some students that are describing an element's chemical properties.

I'd like you to write down the names of which students are describing an element's chemical properties.

It might be one or it might be more than one.

Aisha, "How shiny an element is." Andeep, "How an element will react with other chemicals." Lucas, "When an element is strong." Jacob, "New substances are formed when it reacts.

Sofia, "The boiling point of an element." Pause the video now, then write down the name of the student or students that is describing an element's chemical properties.

Well done if you said that Andeep and Jacob are describing an element's chemical properties.

So Andeep said how an element will react with other chemicals, and Jacob said that new substances are formed when it reacts.

So well done if you got that one correct.

Now on to part two, which student or students are describing an element's physical properties? So just like before, one or more students are describing an element's physical properties.

Write down the name of all those students.

So we've got Aisha, "An element's melting point.

Andeep, " If an element reacts with chlorine." Lucas, "If an element is hard." Jacob, "If an element is unreactive." Sophia, "The temperature that silver melts at." Pause the video for some thinking time, complete the task, then press play when you've got your answer or answers.

Well done for working really hard.

So let's have a look see which students are describing the element's physical properties.

So three students this time.

Aisha said an elements melting point.

Lucas said if an element is hard, and Sophia said the temperature that silver melts at.

So well done if you've got all of those correct.

They're all physical properties.

Now we're gonna have a look at the element silver.

So silver's an element and here's a list of silver's properties.

I want you to sort them into chemical properties and physical properties.

So two lists, chemical properties, physical properties, and then I want you to just sort these into them.

So melting point, 962 degrees C, hard, reacts with chlorine, makes new substances when in contact with oxygen, will conduct electricity, reacts with hydrochloric acid, can be bent into different shapes, shiny when polished.

Pause the video now and press play when you're ready for your answers.

Here's my two lists here.

I've got physical properties of silver and chemical properties of silver.

Melting point, so the melting point is a physical property.

Hard is a physical property.

Reacts with chlorine is a chemical property because new substances will be made.

Because it makes new substances when in contact with oxygen, that is a chemical property.

Will conduct electricity.

That is a physical property.

Reacts with hydrochloric acid.

That is a chemical property.

And can be bent into different shapes.

That's a physical property, that's malleable.

And shiny when polished.

So that is a physical property of silver.

So well done if you've got all of those ones correct.

Here's a summary of everything you should have learned during the properties of elements lesson: Elements are chemically pure, but can react together.

Each element has a fixed melting and fixed boiling point.

Each element has a particular physical and chemical properties.

The properties of elements are different from those of a single atom.

And elements with similar properties are arranged together in the periodic table.

Well done for working hard during this lesson.

I know it wasn't always easy to complete those tasks, however, I'm sure you know much more about the properties of elements than you did before starting this lesson so well done.