Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. In mass terms, Iron is the most abundant element forming planet Earth as a whole. Much of the Earth's outer and inner core is composed of iron. It is the fourth most common element in the Earth's crust. Iron's significant presence in the composition of rocky planets like Earth is due to its abundant production resulting from the fusion in high-mass stars, where the production of nickel-56 (which decays to iron) is the last nuclear fusion reaction that is exothermic. This allows radioactive nickel to become the last element to be produced before the collapse of a supernova causes the scattering of this precursor radionuclide of iron into space. Elemental iron can be found in meteoroids and other low oxygen environments. Iron is reactive to oxygen and water, causing rust on its otherwise pure silvery-gray sheen.
Iron plays an important role in biology, forming complexes with molecular oxygen in hemoglobin and myoglobin; these two compounds are common oxygen transport proteins in vertebrates. Iron is also the metal used at the active site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants and animals.
Pure iron is soft (softer than aluminum), but significantly hardened and strengthened by impurities from the smelting process, such as carbon. A small proportion of carbon produces steel, which may be up to 1000 times harder than pure iron.
NEPTUNE’S MEDICINE CHEST
I was kind of floored by the article “Neptune’s Medicine Chest,” particularly because I was naïve to the ways of scientific discovery and couldn’t fathom how someone could figure out than an obscure ocean fungus could have cancer-curing qualities. Little did I know the intense scrutiny and collection process whereby Fenical collects many different plants and fungi in the ocean and isolates the chemicals of these living materials and tests them all against every kind of bacteria, cancer, and fungi they have in lab. I also find it amazing that within the ecosystem of Earth, though malignant pathogens occur in nature, if one searches hard enough, s/he can also find in nature the antidote to that pathogen. I was glad to hear that the ocean still has living organisms capable of healing people because I was very saddened by pictures in which plastic particles in a sample of average ocean water out-numbered the amount of plankton. That might not sound like it has any bearing on us, except for if you eat shrimp, because shrimp eat plastic particles thinking it’s plankton. Seaweed might have cancer-helping properties, but I bet you shrimp has cancer-causing properties. I still eat it anyway.
REVIEW OF THE LINK: http://www.visionlearning.com/library/module_viewer.php?mid=55
This link re-iterates the small miracle of a harmless compound formed from two dangerous elements that most people don’t have the first clue are dangerous! Sodium produces flames when it gets wet, and chlorine is a poisonous gas used as a weapon in World War 1, but when you add these two elements together, you get sodium chloride otherwise known as common table salt!
This site also gives a simple but information-packed look at the properties of ionic and covalent bonds. Ionic bonds occur when one atom completely transfers one of its electrons to another atom and then these oppositely charged ions electrostatically attract each other to form solids. Ionic bonds are typically formed between metals and non-metals, dissolve easily in water, have high melting temperatures, and conduct electricity well. Covalent bonds, on the other hand, most commonly occur between two non-metals when a non-metal atom attracts an electron from another non-metal atom in the atoms mutual attempt to fill up their valence shells. Covalent bonds form true molecules that are not positively or negatively charged, hence they don’t tend to attract each other and form gases and liquids where these molecules move about freely. This link provides solid info of different types of covalent bonds, Lewis Dot structures, and dipoles.
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