Page 46 - Curriculum Visions Dynamic Book

Oxygen group elements
Another term for the group 6 elements
in the Periodic Table (also called the chalcogens).The members of the group are oxygen (O), sulphur (S), selenium (Se), tellurium (Te) and polonium (Po).
Discovery
Oxygen was discovered in 1772 by the Swedish chemist Carl Wilhelm Scheele. It was discovered independently by the English chemist Joseph Priestley in 1774. Because Priestley was the first to publish his findings, the discovery is usually attributed to him.
 The oxygen cycle.
Technology
Oxygen is frequently used for combustion, such as in oxyacetylene welding. As a
pure gas it can help people with breathing problems. In spacecraft it is part of the
fuel system.
Geology
Oxygen makes up 89% by weight of sea water and 47% by weight of the Earth’s crust.
Biology
Oxygen is vital for life.About two-thirds of the human body is oxygen.Animals take in oxygen and give out carbon dioxide. Plants take in carbon dioxide and give out oxygen. As a result, almost
At night plants absorb oxygen and emit carbon dioxide.
The oxygen reservoir is the atmosphere.
During the day plants absorb carbon dioxide and emit oxygen through photosynthesis.
Dead organic matter is oxidised in the soil; minerals are oxidised as they are weathered.
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Animals respire, absorbing oxygen and exhaling carbon dioxide.
Oxygen is absorbed and released by oceans.