oxygen

o

oxygen

Symbol: O
Atomic Number: 8
Atomic Weight: 15.9994
Element Classification: Non-Metal
Discovered By: Joseph Priestly, Carl Wilhelm Scheele
Discovery Date: 1774 (England/Sweden)
Name Origin: Greek: oxys and genes, (acid former).
Melting Point (K): 54.8
Boiling Point (K): 90.19

oxygen

In 1929, W. F. Giaque and H. L. Johnston announced the discovery of two isotopes of oxygen, of mass numbers 17 and 18.On Earth, oxygen is more common than any other element. It is an invisible, odourless gas that makes up 21 per cent of air. Oxygen is found in water, minerals, and almost all living things. It is essential to life.Almost all living things, including humans, need oxygen to survive. Both plants and animals take in oxygen from their surroundings to release energy. Underwater plants and animals cannot use the oxygen in air – instead they use oxygen dissolved in water.http://mel.org/index.php?P=SPT--BrowseResources&ParentId=833