Search results
Results from the WOW.Com Content Network
Helium-4 is an unusually stable nucleus because its nucleons are arranged into complete shells. It was also formed in enormous quantities during Big Bang nucleosynthesis. [113] Helium-3 is present on Earth only in trace amounts. Most of it has been present since Earth's formation, though some falls to Earth trapped in cosmic dust. [114]
The noble gases helium, neon, argon, krypton, xenon are nonreactive and have no known direct biological role — albeit xenon nevertheless very surprisingly exhibits both anesthetic and neuroprotective side-effects despite usually being considered "chemically inert," and can activate at least one human transcription factor. (Radon is ...
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
Helium is inert - it does not react with other substances or combust - and its atomic number is 2, making it the second lightest element after hydrogen. Rockets need to achieve specific speeds and ...
Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures.Liquid helium may show superfluidity.. At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C (−452.20 °F; 4.15 K).
Helium's first ionization energy of 24.57 eV is the highest of any element. [2] Helium has a complete shell of electrons, and in this form the atom does not readily accept any extra electrons nor join with anything to make covalent compounds. The electron affinity is 0.080 eV, which is very close to zero. [2]
For humans, we're 99.9 percent similar to the person sitting next to us. The rest of those genes tell us everything from our eye color to if we're predisposed to certain diseases.
Since the dawn of time, humans have asked what makes us so special. After a recent study conducted at the University of California, humans may now have a glimpse into the answer to that age old ...