Carbon is a chemical element( A chemical element or element is a species of atoms having the same number of protons in their atomic nuclei (i.e. the same atomic number)),with symbol C and atomic number 6.
Atomic Number is the number of protons found in the nucleus of an atom of that element. Remember proton is a subatomic particle, symbol p or p+, with a positive electric charge of +1e elementary charge
Carbon is the fourth most abundant element in the universe, and is absolutely essential to life on earth. Every organism on Earth needs carbon either for structure, energy, or, as in the case of humans, for both. Discounting water, YOU are about half carbon. Additionally, carbon is found in forms as diverse as the gas carbon dioxide (CO 2 ), and in solids like limestone (CaCO 3 ), wood, plastic, diamonds, and graphite.
Carbon is the lightest element on the periodic table that has four valence electrons. If each valence electron is used to form a bond with another atom, carbon reaches 8 electrons in its valence shell and is stable. Elements with either less or more than 4 valence electrons can only form a maximum of 3 covalent bonds, this is why 4 is a magic number and why carbon is special.
Compounds of Carbon
Compounds of carbon are defined as chemical substances containing carbon. More compounds of carbon exist than any other chemical element except for hydrogen. Organic carbon compounds are far more numerous than inorganic carbon compounds. In general bonds of carbon with other elements are covalent bonds.
KEY POINTS:*Organic chemistry is often defined as the chemistry of carbon*
The chemistry of carbon is dominated by three factors.
1. Carbon forms unusually strong C-C single bonds, C=C double bonds, and carbon-carbon triple bonds.
2. The electronegativity of carbon (EN = 2.55) is too small to allow carbon to form C4-ions with most metals and large for carbon to form C4+ ions when it reacts with nonmetals. Carbon therefore forms covalent bonds with many other elements.
3. Carbon forms strong double and triple bonds with a number of other nonmetals, including N, O, P, and S.
Allotropes of Carbon
Carbon occurs as a variety of allotropes. There are two crystalline forms diamond and graphiteand a number of amorphous (noncrystalline) forms, such as charcoal, coke, and carbon black.
The properties of diamond are a logical consequence of its structure. Carbon, with four valence electrons, forms covalent bonds to four neighboring carbon atoms arranged toward the corners of a tetrahedron, Each of these sp3-hybridized atoms is then bound to four other carbon atoms, which form bonds to four other carbon atoms, and so on. As a result, a perfect diamond can be thought of as a single giant molecule. The strength of the individual C-C bonds and their arrangement in space give rise to the unusual properties of diamond.
Graphite consists of extended planes of sp2-hybridized carbon atoms in which each carbon is tightly bound to three other carbon atoms. (The strong bonds between carbon atoms within each plane explain the exceptionally high melting point and boiling point of graphite).