Oxygen
21oxygen-18 — noun A minor stable isotope of oxygen, , having eight protons and ten neutrons; it amounts to about 0.2% of the element in nature See Also: oxygen 16, oxygen 17 …
22oxygen-18 — A stable oxygen isotope making up 0.20% of natural oxygen; used in mass spectrometry and in NMR studies of tissue. SYN: heavy oxygen …
23oxygen — [[t]ɒ̱ksɪʤən[/t]] N UNCOUNT Oxygen is a colourless gas that exists in large quantities in the air. All plants and animals need oxygen in order to live. The human brain needs to be without oxygen for only four minutes before permanent damage… …
24oxygen — A colorless, odorless, tasteless, non explosive gas, it is the most abundant element on earth, constituting about half of the surface material. It makes up about 9/10 of water, two thirds of the human body, and 1/5 (by volume) of air. Normal… …
25oxygen — n. an odourless colourless gas that makes up one fifth of the atmosphere. Oxygen is essential to most forms of life in that it combines chemically with glucose (or some other fuel) to provide energy for metabolic processes. It is absorbed into… …
26oxygen-16 — The common oxygen isotope, making up 99.76% of natural oxygen …
27oxygen-17 — The rarest of the stable oxygen isotopes, making up 0.04% of natural oxygen …
28oxygen 15 — an artificial radioactive isotope of oxygen, atomic mass 15, having a half life of 2.04 minutes; it decays by positron emission (1.70 MeV) and is used as a tracer in the measurement of regional blood volume and flow and oxygen metabolism by… …
29oxygen — [18] Etymologically, oxygen means ‘acid former’. The word was coined in French in the late 1780s as oxygène, based on Greek oxús ‘sharp, acid’ (a descendant of the same Indo European base, *ak ‘be pointed’, as produced English acid, acute, etc)… …
30oxygen — In its free form, a colorless, tasteless, and odorless gaseous element. The second most abundant gas in the earth’s atmosphere and a prerequisite for virtually all forms of animal life. It makes up 20.946% of dry air by volume, and its molecular… …
