Carbon, ground-state electron

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Here, the bonding between carbon atoms is briefly reviewed fuller accounts can be found in many standard chemistry textbooks, e.g., [1]. The carbon atom [ground state electronic configuration (ls )(2s 2px2py)] can form sp sp and sp hybrid bonds as a result of promotion and hybridisation. There are four equivalent 2sp hybrid orbitals that are tetrahedrally oriented about the carbon atom and can form four equivalent tetrahedral a bonds by overlap with orbitals of other atoms. An example is the molecule ethane, CjH, where a Csp -Csp (or C-C) a bond is formed between two C atoms by overlap of sp orbitals, and three Csp -Hls a bonds are formed on each C atom. Fig. 1, Al. 

We would normally write the electronic ground state electron configuration of a carbon atom as ls-2s 2p-. Despite the intellectual activity that has gone into defining mythical valence states for carbon atoms in different bonding situations, no one would include a d-orbital in the description of ground state carbon. 

Lets look at the ground state electron configuration and orbital diagram of carbon (6C) which is the first element in group 4A. 

Here, Iq is the electron affinity of C60 (Iq = 2.65 eV [50]). Thus, the 5-potential model ignores the finite thickness nature of the carbon cage within the model, A = 0. Furthermore, in the framework of this model, the size of the embedded atom ra is considered to be so small, compared to the size of C60, that the ground state electronic wavefunctions of the embedded atom coincide exactly with those for a free atom. In other words, the model assumes no interaction between the ground state encaged atom and the carbon cage at all. Therefore, the model is applicable only to the deep inner subshells of the encaged atom. As for the carbon atoms from... 

The benzene molecule contains a ring of six carbon atoms around which six delocalized jt-electrons can circulate. An adaptation of the free-electron model (FEM) for a cyclic molecule predicts a ground-state electron configuration which we can write as Itt as shown in Fig. 6.1. 

The leftmost carbon atom in the structure is sp hybridized, and the other two carbon atoms are sp hybridized. The atoms in the molecule are located on a single straight line, with the exception of the three hydrogen atoms on the leftmost carbon atom, which point outward toward three of the vertices of a tetrahedron. There is a cr bond between each pair of bonded atoms. The p and py orbitals on carbon atoms 2 and 3 combine to form two TT orbitals and two rr orbitals only the former are occupied in the ground-state electron configuration. 

The ground-state electronic configuration of carbon is ls22s22p. 12py1. 

Carbon is a typical main group element due to its properties. It is a nonmetal with the ground state electron configuration [He]2s 2p. The electronegativity of 2.55 on the Pauling scale is quite close to that of adjacent elements in the periodic table, for example, P (2.1), B (2.0), or S (2.5). The first energy of ionization is... 

You may be surprised to learn that carbon forms four covalent bonds since you know that carbon has only two unpaired electrons in its ground-state electronic configuration (Table 1.2). But if carbon were to form only two covalent bonds, it would not complete its octet. Now we need to come up with an explanation that accounts for carbon s forming four covalent bonds. 

The ground state electron distribution of an isolated molecule invariably determines the type of charge with which it favourably interacts. For example, a carbonyl group would be stabilised by an electron acceptor adjacent to the carbonyl oxygen while it would be energetically favourable to have an electron donor near the carbonyl carbon (XVI). The ground state charge distribution, of course, also... 

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