Chest radiograph. A chest radiograph, colloquially called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in medicine.
Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among all the elements.he nucleus of the helium-4 atom is identical with an alpha particle. High-energy electron-scattering experiments show its charge to decrease exponentially from a maximum at a central point, exactly as does the charge density of helium's own electron cloud.
Learn about helium balloons, noble gases, the helium atom, the balloon boy hoax, space related helium storage tanks, how helium can change a personâs voice and much more with our range of interesting helium facts, properties and information.Helium is a chemical element with the symbol He and atomic number 2.Helium is a colorless, tasteless and odorless gas. Helium is the second most common element in the Universe (after hydrogen), making up around 24% of its mass.Helium is part of a group of chemical elements called noble gases, the other five that occur naturally are neon, argon, krypton, xenon and radon.elium is the second most common element in the Universe (after hydrogen), making up around 24% of its mass. Helium is part of a group of chemical elements called noble gases, the other five that occur naturally are neon, argon, krypton, xenon and radon.