Helium

Helium DISCOVERY: A French astronomer, Pierre-Jules-C?sar Janssen (1824-1907), first obtained proof for the existence of atomic number 2 during the solar overshadow of 1868 in India when he detected a new chicken line (587.49 nm) in the solar spectrum very close to the yellowness sodium D-line. It was non possible to produce this line in the laboratory. Sir Norman Lockyer (1836-1920), an face astronomer, recognised that no known element at that era gave this line and named the element helium for the solarize. For many historic period helium was regarded as an element that might exist on the sun although it was unknown on the Earth.

Spectroscopists at the time doubted the results concerning helium. except the claims initiated a search for the new element on major planet earth. In 1895, Sir William Ramsay detect 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 identify helium. It was discovered independ...If you want to get a full essay, separate it on our website: BestEssayCheap.com

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