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Donald Duck voices and floating balloons. Helium is element number 2 on the periodic table. More chemistry at http://www.periodicvideos.com/ Follow us on Facebook at http://www.facebook.com/periodicvideos And on Twitter at http://twitter.com/periodicvideos Periodic Videos films are by video journalist Brady Haran

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1. What can you do if you want to speak like Donald Duck? Why does it happen?
2. What happen if you add a match in a balloon filled with Hydrogen?
3. What do you learn about the things freezed with Helium?
4. Now you know the ballons filled with Helium are so lights. What  happen if you turn loose it?
5. According to the video, why nowadays we use Helium to fill balloons and not Hydrogen? How much does Hydrogen and Helium molecule weight?

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If you cold things with liquid Helium you get very strange properties. You can make some materials lose their electrical resistence. It is used for magnets when you need very powerful magnets and we use this magnets from magnetic resonance imaging in hospitals.
Helium is very important for all sorts of refrigeration.

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In the past Hydrogen be used to fill balloons and actually we can use Helium to do it.
If you fill a balloon with Hydrogen and add a match, it will burn quickly and energetically because it makes water but if you do it with a balloon filled with Helium it will explode but it didn't burn. It's unreactive, it's an inert gas.
If you freeze a balloon of Helium, the gasses inside slow's down because it take up much less volume.
If you breathe Helium you start speaking like Donald Duck because the speed of sound is much greater in Helium that it is in ordinary gases.

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Helium can be used to find leaks because is very small gas and can finds the smallest holes and it's very light too.
Helium is the most unreactive element.
It exists as isolated atoms.
Helium can't be synthesized in nature because it is just an element.

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This element was discovered in 1868 by Pierre Janssen and Norman Lockyer

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Melting point -272,2 ºC
Boiling point -268,6 ºC
The normal phase is gas.
It's a noble gas.

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Helium is composed of two electrons in atomic orbitals and the nucleus contains two protons and two neutrons. (1s²).

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Symbol He
Atomic number 2
Atomic weight 4 g/mol.