Petry,+Micah

=Welcome to Mrs. Bowman's Science pages=

Element: Helium Symbol: He Boiling Point: -272.2 °C (-458°F) Melting Point: -268.93°C (-452.07°F) Density: 214 kg Protons: 2 Neutrons: 2 Electrons: 2 Atomic Mass: 4.002602 amu Atomic Number: 2 Electron Configuration: There are two electrons in the first shell Orbital Notation: 1s² [] How, when and who discovered it: A French astronomer, Pierre-Jules-César Janssen (1824-1907), first found the existence of helium during the solar eclipse of 1868 in India when he detected a new yellow line in the solar spectrum very close to a yellow sodium D-line. It was not possible to produce this line. Sir Norman Lockyer (1836-1920), an English astronomer, recognized that no known element at that time made  t his line and named the element helium for the sun. For many years helium was regarded as an element that could exist although it was unknown on the Earth. Spectroscopists at the time doubted the results about helium. However the claims started a search for the new element on earth. In 1895, Sir William Ramsay discovered helium after treating cleveite, a uranium mineral, with mineral acids. Ramsey sent samples of the gas to Sir William Crookes and Sir Norman Lockyer who identified helium. It was discovered independently in clevite by Cleve and Langley at about the same time. Lockyer and Professor Edward Frankland offered the name helium. [] Where or how produced, process of mined:Typically natural gas deposits (mainly methane, CH4)

contain about 7% helium and some have up to 25%. Chemical and physical properties: [|Refractive index] : 1.000035 (gas; liquid 1.028) (no units) [|Liquid range] : 3.27 K Where is it found: Nobel Gasses Two common chemical reactions: Helium with Halogens Helium doesn’t react with any halogens, Helium with Water Helium does not react with water. It does, however, dissolve slightly to the extent of about 8.61 cm3 kg-1 at 20°C (293 K). Uses: Deep sea diving, Party balloons and blimps Value: $5.20 per 100g Unusual facts: Helium is abundant on earth although it wasn’t discovered until 1835 and that was on the sun []