Iliac crest pain is not that common in the general population, but it is frequent in older individuals, runners (and athletes in general), lower back pain sufferersâ¦ But that doesn`t mean âregularâ people like you and me can`t experience it from time to time!
The mantle is composed of iron-magnesium silicates, and the crust is composed of roughly 5 percent iron. All together, iron makes up an estimated 35 percent of the Earth's mass. Oxygen. Oxygen, the second most abundant element on Earth, is found mainly in the crust.
Source: Oxygen is the most abundant element in the Earthâs crust, accounting for almost half of it by mass. More than half of the atoms in the Earthâs crust are oxygen atoms. About 86 percent of the mass of Earthâs oceans is oxygen â mainly in the form of water. Oxygen is the third most common element in the Universe, behind hydrogen and helium. It is obtained commercially from liquefied air separation plants. It can be prepared in the laboratory by electrolysis of water. Isotopes: 13 whose half-lives are known, with mass numbers 12 to 24.