Oxygen is a chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.
Properties of Oxygen:
Physical State: Oxygen is a colorless, odorless, and tasteless gas at room temperature and pressure.
Chemical Reactivity: It is highly reactive and forms compounds with almost all other elements, as well as with many organic compounds.
Role in Combustion: Oxygen supports combustion, and many materials ignite and burn more vigorously in its presence.
Role in Ozone Layer: In the Earth's atmosphere, oxygen plays a crucial role in the formation and maintenance of the ozone layer, which protects life on Earth by filtering out harmful ultraviolet radiation from the sun.
Study Guide:
Here are some key points to remember about oxygen:
History and Nature of Science: A student should understand the history and nature of science. A student who meets the content standard should:
Develop an understanding that historical perspectives of scientific explanations demonstrate that scientific knowledge changes over time, building on prior knowledge.
Develop an understanding that scientific knowledge is ongoing and subject to change as new evidence becomes available through experimental and/or observational confirmation(s).