Practice English Speaking&Listening with: Physical properties of group 1 elements

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- Hi - Hiya

What reactions have you got to show me then?

I thought we'd start with Group 1.

What I've done is I've got the Group 1 elements out to have a look at.

As you see them down the periodic table, so lithium, sodium, potassium, rubidium and caesium.

What I thought we'd do is just have a look at how easy they are to cut

and then see what happens when they're exposed to the air when we clean off the oil.

Lithium's actually quite hard to cut.

If I just move that bit away you can see that the surface is quite shiny

and it'll just gradually start to react and tarnish. - You can see it tarnishing already.

Sodium's much easier to cut.

It's almost like cutting cheddar cheese, it's that sort of consistency

and if I just cut a slice off there, and you'll see

that that tarnishes much more quickly.

You can see the surface is going.

Potassium's really easy, and tarnishes almost immediately.

If you just sort of move the oil off the surface you can see that it tarnishes, the blue, bluey-purple tarnish on the surface.

- Now you can't cut rubidium and caesium can you?

- No, rubidium and caesium are stored under argon

in these sealed glass containers.

You can see what the actual alkali metals look like when they've got no tarnish on them.

Very shiny silvery metals and caesium's quite interesting because it's got

a low enough melting point that you can actually melt it from the heat of your hand.

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