So, this is a sample of Rubidium. It arrived just a couple of days ago, from Alpha the
company, so there is one gram of Rubidium, it costs about £65. It is one of the alkali
metals, so it is very, very reactive, a bit like sodium but perhaps a little bit more.
So the metal itself is quite low melting, it won’t melt in my hand though unfortunately,
so I am not going to show you it liquid now, but you can see there is one gram of the metal
inside this glass ampoule. It’s very reactive, and we are going to explore its chemistry
now by putting this into some water. Well we’ve got this really neat device which
Neil put together last Friday and you can see it’s got a hammer which is going to
break the glass.
Show us Neil, what does it do mate?
So when the hammer falls, literally, we will break the glass, the rubidium will just drop
into the big bucket of water that we’ve got underneath.
Rubidium is an alkali metal that comes between potassium and caesium and both potassium and
caesium are much better known among chemists than rubidium. Potassium because it is all
over the world, the environment, you have potassium in cells and plants and so on, I
mean biological cells. Rubidium on the other hand is quite rare.
So I am going to give the sample now to Neil and Neil is going to load it and we are going
to drop the hammer on it. There you go Neil.
It was discovered originally by the German chemist Bunsen or ‘Bunsen’ as he was called,
the one who invented the Bunsen burner and he discovered it by looking at the colours
that you see in flames, when he was heating up water that came from, mineral water that
came from springs somewhere in Germany I believe, or it may have been somewhere in middle Europe.
So Neil is arranging the sample of Rubidium against the metallic back plate in the small
metallic collider.
Rubidium gives a characteristic colour that is different from lilac of sodium or, I’m
sorry, lilac of potassium or the orange of sodium.
The rubidium is slightly more reactive than sodium so when we did the sodium experiments,
we had our safety glasses and coat on, but for rubidium we are going to wear secondary
goggles, so here’s my safety goggles, which I am going to put on top. Don’t we look
good.
Nowadays, one of the main uses of rubidium, is actually in physics rather than in chemistry
because you can heat up rubidium metal to a high temperature and get a vapour of rubidium
atoms in a specially constructed heated cell and you can get very interesting effects from
shining very intense laser light into rubidium atoms, and the rubidium atoms can do a whole
series of different, very elegant physics experiments. So rubidium has got a life of
its own in physics but in chemistry, it’s perhaps slightly neglected.
Was that it?
Don’t think I needed my safety screen.
Well that wasn't very exciting was it?
There still could be some in there.
It's all gone.
You were right it was just a fizzle.