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I stopped reading at: "composed of carbon atoms joined in a pattern that makes the material extremely tough and impervious to even the smallest atom, helium."
by marshray 9y ago
I stopped reading at: "composed of carbon atoms joined in a pattern that makes the material extremely tough and impervious to even the smallest atom, helium."
Is helium really smaller than hydrogen?
- Lozzer 9y agoIf you belive Wikipedia https://en.wikipedia.org/wiki/Atomic_radius https://en.wikipedia.org/wiki/Atomic_radius then the atomic radius of Helium has never been measured, but it is predicted to be smaller than Hydrogen.
- joshuas 9y agoA google search says yes.
- mattchamb 9y agoWell, I'm not a physicist, but hydrogen gas is two atoms compared to 1 atom for helium gas.
- deleted 9y ago[deleted]
- DrScump 9y agohydrogen gas is two atoms ... which makes it a molecule.
- MertsA 9y agoOddly enough yes Helium has a smaller atomic radius because the additional proton and electron complete that first electron shell and get pulled closer to the nucleus.
- pygy_ 9y agoAlso, atomic Hydrogen is not very common around here (nor anywhere, I suppose)... H+ and H2, on the other hand...
- DmenshunlAnlsis 9y agoHelium is a strange bird. Every other element in liquid form will freeze if you drop the temperature enough, except Helium. You must greatly pressurize Helium for it to freeze. It is worth pointing out that while the atomic radius of Helium is smaller than Hydrogen, Helium is still the heavier element. It’s small radius and tendency to remain a gas or liquid makes it very useful in testing for leaks or as a purging gas.
- burfog 9y agoHydrogen is mighty weird too. For leak testing, it can be better than helium because the molecule is lighter. This raises the speed for any given temperature, and thus increases the rates of diffusion and effusion. A downside is that hydrogen can burrow right into solid metal, one atom (proton) at a time, and then merge back into diatomic molecules. This creates a sort of internal pressure in the material, making it brittle. Hydrogen embrittlement is a significant problem, particularly with titanium.
- MertsA 9y agoThat's an understatement. Helium cooled below 2K loses literally all viscosity and will flow through porcelain like it's a sponge. Not only that, because there's literally zero viscosity, convection makes superfluid helium a great heat conductor. All of this was discovered back in the 30s. The man who discovered superfluid liquid helium must have truly thought he had gone insane.