Chlorine nonbonding electron pairs

How many nonbonding electron pairs are there per atom in chlorine, sulfur, phosphorus, and silicon ... 

Figure 12.20 By drawing Lewis structures you can show that there are three (chlorine), two (sulfur), one (phosphorus), and zero (silicon) nonbonding electron pairs per atom.

Note that the nonbonding electron pairs have been deleted from oxygen, nitrogen, sulfur, and chlorine for simpUcity. 

A water molecule uses one of the nonbonding electron pairs to form a bond to a proton of HCI. The bond between the hydrogen and chlorine breaks, and the eiectron pair goes to the chiorine atom. 

Figure 3-5 Approximate orbital description of the abstraction of a hydrogen atom by a chlorine atom to give a methyl radical and hydrogen chloride. Notice the rehybridization at carbon in the planar methyl radical. The additional three nonbonded electron pairs on chlorine have been omitted. The orbitals are not drawn to scale. The symbol 1 identifies the transition state.

The chlorine atom in CIF3 is bonded to three other atoms and has two nonbonding electron lone pairs. Both lone pairs occupy equatorial positions, resulting in a T shape for the C1F3 molecule. (As with the seesaw, you have to tilt your head... 

In order of increasing energy, the outermost orbitals associated only with the C=S chromophore are (cr), ( )> (71), (n), (tc ), and (cr ), where n is the thiocar-bonyl nonbonding orbital, and n a second nonbonding orbital, (chlorine orbitals are excluded). The electronic configuration of the ground state can be written (a)2(nr)2(n)2(n)2(n )0(a )0, where each of the inner orbitals are doubly occupied by an electron pair and the outer orbitals (virtual) are empty. 

Oxidations involving loss of a lone-pair (nonbonding) electron rather than a n electron are observed in the reactions of amines with electron acceptors (potassium ferricyanide, chlorine dioxide). In the case of a tertiary aliphatic amine, the result is cleavage of an alkyl group i.e.. 

A covalent bond also occurs in Cl. In the chlorine molecule, the two chlorine atoms are attracted to the same pair of electrons. Each chlorine atom has seven valence electrons in the third energy level and requires one more electron to form an electron core with an argon electron configuration. Each chlorine atom contributes one electron to the bonded pair shared by the two atoms. The remaining six valence electrons of each chlorine atom are not involved in bonding. They are variously called nonbonding electrons, lone pair electrons, or unshared electron pairs. 

Objective 12 The nonbonding pairs of electrons are called lone pairs. Each atom of chlorine in a CI2 molecule has 1 covalent bond and 3 lone pairs. 

The centers of charges of the chlorine hybrids are located at the corners of a square. A sp d f hybridization will require a too weak interplanar distance c, which is incompatible with the presence of doubly used nonbonding orbitals carried by platinum atoms (high electron density corresponding to the classical lone pairs). Consequently the distance a between platiniam atoms will be larger than c. The system is quadratic. 

We can write the acid—base reaction shown above with curved arrows to indicate the movement of pairs of electrons during the proton transfer process. Electrons move from the start of the arrow toward the arrow head. The sequence of arrows in the reaction as it is written below shows that a nonbonded pair of electrons of the oxygen atom of water forms a bond to the hydrogen atom of HCl and the bonded pair of electrons in the H—Cl bond moves to the chlorine atom. 

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