chapter  2
76 Pages

Carbon Properties

Without the element carbon, life as we know it would not exist. In

this sense, this is one of the most important elements. Pure carbon

has extremely low toxicity and can be handled and even ingested

safely. It is the fourthmost abundant element in the universe bymass

after hydrogen, helium, and oxygen but amounts to less than 0.1%

in the earth crust. However, few millions of compounds, including

carbon, are reported and synthesized regularly. Carbon has six

electrons. Two of them will be found in the 1s orbital close to the nucleus, the next two going into the 2s orbital. The remaining ones will be in two separate 2p orbitals. The electronic structure of carbon is normally written in the form 1s22s22p1x2p

1 y or more

commonly 1s22s22p2 because the p orbitals have the same energy. Table 2.1 gives the first transition observed in the excited state

(2s22p2 to 2s2p3). For the sake of comparison, the same transition energy is given for all group IV elements.