Carbon is an incredible element. Arrange carbon atoms in one way, and they become soft, pliable graphite. Re-jigger the arrangement, and — presto! —atoms form diamond, one of the hardest materials in the world.
Carbon occurs naturally as carbon-12, which makes up almost 99 percent of the carbon in the universe; carbon-13, which makes up about 1 percent; and carbon-14, which makes up a minuscule amount of overall carbon but is very important in dating organic objects.
Just the facts,
Atomic Number (number of protons in the nucleus): 6
Atomic Symbol (on the Periodic Table of Elements): C
Atomic Weight (average mass of the atom): 12.0107
Density: 2.2670 grams per cubic centimeter
Phase at Room Temperature: Solid
Melting Point: 6,422 degrees Fahrenheit (3,550 degrees C)
Boiling Point: 6,872 F (3,800 C) (sublimation)
A number of isotopes: 15 total; two stable isotopes, which are atoms of the same element with a different number of neutrons.
Most common isotopes: carbon-12 (6 protons, 6 neutrons and 6 electrons) and carbon-13 (6 protons, 7 neutrons and 6 electrons)
Carbon from starting to life
As the sixth-most abundant element in the universe, carbon forms in the belly of stars in a reaction called the triple-alpha process. In older stars that have burned most of their hydrogen, leftover helium accumulates. Each helium nucleus has two protons and two neutrons. Under very hot temperatures — greater than 100,000,000 Kelvin (179,999,540.6 F) — the helium nuclei begin to fuse, first as pairs into unstable 4-proton beryllium nuclei, and eventually, as enough beryllium nuclei blink into existence, into a beryllium plus a helium. The result: Atoms with six protons and six neutrons — carbon.
Carbon is a pattern maker. It can link to itself, forming long, resilient chains called polymers. It can also bond with up to four other atoms because of its electron arrangement. Atoms are arranged as a nucleus surrounded by an electron cloud, with electrons zinging around at different distances from the nucleus. Chemists conceive of these distances as shells and define the properties of atoms by what is in each shell. Carbon has two electron shells, with the first holding two electrons and the second holding four out of a possible eight spaces. When atoms bond, they share electrons in their outermost shell. Carbon has four empty spaces in its outer shell, enabling it to bond to four other atoms. (It can also bond stably to fewer atoms by forming double and triple bonds.)
In other words, carbon has options. And it uses them: Nearly 10 million carbon compounds have been discovered, and scientists estimate that carbon is the keystone for 95 percent of known compounds, according to the website Chemistry Explained. Carbon's incredible ability to bond with many other elements is a major reason that it is crucial to almost all life.
Carbon's discovery is lost to history. The element was known to prehistoric humans in the form of charcoal. Carbon as coal is still a major source of fuel worldwide, providing about 30 percent of energy worldwide, according to the World Coal Association. Coal is also a key component in steel production, while graphite, another form of carbon, is a common industrial lubricant.
Carbon-14 is a radioactive isotope of carbon used by archaeologists to date objects and remains. Carbon-14 is naturally occurring in the atmosphere. Plants take it up in respiration, in which they convert sugars made during photosynthesis back into energy that they use to grow and maintain other processes, according to Colorado State University. Animals incorporate carbon-14 into their bodies by eating plants or other plant-eating animals. Carbon-14 has a half-life of 5,730 years, meaning that t after that time, half of the carbon-14 in a sample decays away.
Because organisms stop taking in carbon-14 after death, scientists can use carbon-14's half-life as a sort of clock to measure how long it has been since the organism died. This method works on once-living organisms, including objects made of wood or other plant material.
A carbon nanotube
A carbon nanotube (CNT) is a minuscule, straw-like structure made of carbon atoms. These tubes are extremely useful in a wide variety of electronic, magnetic, and mechanical technologies. The diameters of these tubes are so tiny that they are measured in nanometers. A nanometer is one-billionth of a meter — about 10,000 times smaller than a human hair.
Carbon nanotubes are at least 100 times stronger than steel, but only one-sixth as heavy, so they can add strength to almost any material, according to nano Science Instruments. They are also better than copper at conducting electricity and heat.
Nanotechnology is being applied to the quest to turn seawater into drinking water. In a new study, scientists at Lawrence Livermore National Laboratory have developed a carbon nanotube process that can take the salt out of seawater far more efficiently than traditional technologies.
For example, traditional desalination processes pump in seawater under high pressure, sending it through reverse osmosis membranes. These membranes then reject all large particles, including salts, allowing only clean water to pass through. However, these desalination plants are very expensive and can only process about 10 percent of a county's water needs.
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