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EE UU, , j 3s and, cant 3d orbitals. Now 3.3 ane, , ctron to higher ony ys ‘etrahedral geomettY. Three, This can be achieved by "sara rid orbitals to ae - and one oxygen ion to form, three 3p orbitals of chlorine hybridise ¢ bital of two OXYBE sh the 2p orbital of, id orbi iththe half-filled 2p 01" ine overlap with the <p, 2 7 a Pe SN ybridised half-filled orbitals of chlorin, —O sigma, oxygen atoms to form two a-bonds., In C10j, there are three bonding pairs of ele, ion has a pyramidal structure as shown in Fig. 5.27. | te, |ON THEORY, , [ET] VALENCE SHELL ELECTRON PAIR/REPULSION THE” setters VSEPR, ich is of ia, The valence shell electron pair repulsion theory, which 1s often abbrev jements as the central atom., , €, is a very simple way of predicting the shape of molecules that have main aie, a i initially, It is based upon the repulsive interactions between electron pairs 1m the valen ;, , . ; Nyholm in 1957. According, formulated by Sidgwick and Powell in 1940, and was finally refi ned by Geer ne from each other in three, to the VSEPR theory, pair of electrons repel each other and will remain as ar ap, dimensional space as possible., , The salient features of VSEPR theory are :, , 1. The geometry of the molecule depends upon the total numbe, or non-bonded) around the central atom., , 2. Electron pairs try to stay as far apart as possible to acquire a state O, maximum stability., , 3. Repulsion between the lone pair-lone pair is different from the lone pair-bond pair and bond pair-bond, pair. The repulsive interaction decreases in the order., , Lone pair-Lone pair > Lone pair-Bond pair > Bond pair-Bond pair, , 4. The magnitude of repulsions between the bonded pairs of electrons depends upon the electronegativity, difference between the central atom and the other atoms., , Let us apply the VSEPR theory to simple symmetrical molecules in which all the electron pairs around the, central atom are single covalent bonds. Let us consider a molecule AB,, where the central atom A forms n, number of electron pair bonds with the atom B. Depending upon the number of electron pairs, the molecules, will have different geometries as given in Table 5.3., , i ee eee, TABLE 5.3. Geometries predicted by VSEPR for molecules that contain only, single covalent bonds around the central atom., , one 3s and one 3p ele, , ing pair of electron. As a result, the, , ctrons and one non-bond, , r of valence shell electron pairs (bonded, , f minimum energy and hence, , , , Type No. of electron pairs, , AB, 2