Iron
From Palaeos.org
Iron (from the Old English īren) is the element with the atomic number 26 and symbol Fe (from the latin name for the element, ferrum). It is the 6th most abundant element in the universe and it is a silvery solid metal that is used in the making of alloys.
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History
Iron is the most abundant element in the Earth by mass (34.6%) and is a major component of the core along with nickel. In the early history of the Earth, an event known as the Iron Catastrophe, allowed the heavy element to sink down into the center center of the Earth. Once the element reached the said center, it cooled down and formed the modern core. This crucial and decisive phenomenon set up the overall structure of our planet.
Fe has been known to man for centuries. The wide use of iron in weapon-making started around 1200 BCE in the near east, as a result, historians generally name this period of time the Iron Age. In the modern day, it is the most most used of all metals, often being being employed in steel making and the manufacturing of food containers.
Chemical Properties
Iron is classified as a transition metal in group 8. It is reactive enough so that is does not exist in its pure form in nature, rather, it exsts in compounds such as rust. It is known as ferrous when it is in its +2 oxidation state and as ferric when it is in its +3 oxidation state.
It is also an example of an element that displays allotropy in nature; its three allotropes are alpha, gamma and delta.
Iron is generally extracted from its ore (usually haematite) in a blast furnace through the following chemical processes:
1) C + O2 → CO2
- In this case, coke is heated to form carbon dioxide. The heat that is given off from this exothermic reaction is used in later parts of the extraction technique.
2) C + CO2 → 2CO
- In this step, the carbon dioxide burns with carbon to give off carbon monoxide at the bottom furnace. The CO is used as a reducing agent in the furnace.
3) Fe2O3 + 3CO → 2Fe + 2CO2
- This is the part where the magnetite is burnt with carbon to purify the iron. Fe can be taken from the furnace in its liquid form since the the amount of heat is good enough to melt it.
General Characteristics
* Name, symbol and atomic number: Iron, Fe, 26 * Classification: Transition metal * Appearance: silvery * Group: 8 * Block, period: d, 4 * Electrons per shell: 2, 8, 14, 2
Physical, Atomic and Chemical Characteristics
* Phase at room temperature: solid * Density: 7.874 kg/m³ * Melting point: (1538 °C) (2800 °F) (1811 K) * Boiling point: (2862 °C) (5182 °F) (3134 K) * Heat of fusion: 13.81 kJ mol^-1 * Oxidation numbers: 2, 3, 4 ,6 (bold most stable) * Electronegativity: 1.83 (Pauling scale)
Sources and Further Reading
http://www.webelements.com/iron/
http://www.lenntech.com/periodic-chart-elements/Fe-en.htm
http://rainbow.ldeo.columbia.edu/courses/v1001/first3bill.html
