Specialty Medical Coding Certification. 1  Hematology and Oncology â CHONCâ¢. 2  Internal Medicine â CIMCâ¢. 3  Interventional Radiology and Cardiovascular â CIRCCÂ®. 4  Obstetrics Gynecology â COBGCâ¢. 5  Ophthalmology â COPCâ¢. 6  Orthopaedic Surgery â COSCâ¢. 7  Otolaryngology â CENTCâ¢. 8  Pediatrics â CPEDCâ¢. FREE Practice Exam & Study Guide through Aug 31st.
Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetallic element and oxidizing agent that readily forms compounds (notably oxides) with most elements. Photosynthesis releases oxygen, and respiration consumes oxygen.
Water Isotopes (return to top). Oxygen has three stable isotopes, 16 O, 17 O, and 18 O; hydrogen has two stable isotopes, 1 H and 2 H (deuterium), and one radioactive isotope, 3 H (tritium), which is discussed separately. Oxygen and hydrogen are found in many forms in the earth's hydrosphere, biosphere, and geosphere.