| He | Helium | Atomic number : 2 Relative atomic mass (12C = 12.0000) : 4.002602 |
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| P H Y S I C A L D A T A | |
| Group 18 noble gas Density / kg m-3 : n.a. [s.]; 128.8 [liq., b.p.]; 0.1785 [gas, 273 K] |
Melting point / K : 0.95 (under pressure) Boiling point / K : 4.216 |
| D I S C O V E R Y | |
| Helium was observed in the sun's spectrum during the eclipse of 1868 by Norman Lockyer and Edward Frankland. |
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| G E O L O G I C A L D A T A | |
| Abundances Sun (relative to H = 1 × 1012) : 6.31 × 1010 Earth's crust / p.p.m. : 0.008 Atmosphere / p.p.m. (volume) : 5.2 Residence time / years : n.a. Oxidation state : 0 |
Seawater / p.p.m. : 4 × 10-6 |
| B I O L O G I C A L D A T A | |
| Level in humans Blood / mg dm-3 : trace Bone / p.p.m. : nil Liver / p.p.m. : nil Muscle / p.p.m. : nil |
Daily dietary intake : n.a., but low Total mass of element in average (70 kg) person : n.a., but very small |
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A portrait of helium is available on the Visual Elements site. Up to 200 individual items of information on this element are available in The Elements. |