iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. Its abundance in rocky planets like Earth is due to its abundant production as a result of stellar nucleosynthesis, primarily by neutron capture processes during the supernova stage of a star's life. Iron is a relatively reactive metal and forms its oxides when exposed to oxygen. It rusts when exposed to water and oxygen. It is used in the production of steel, which is widely used in construction and various industrial applications. Iron is also an essential element for life, playing a role in various biological processes. It is found in the human body in the form of hemoglobin, which carries oxygen in red blood cells.