Tetrahedral electron-group arrangement

Step 3. Predict the bond angle For the tetrahedral electron-group arrangement, the ideal bond angle is 109.5°. There is one lone pair, so the actual bond angle should be less than 109.5°. 

Name all the molecular shapes that have a tetrahedral electron-group arrangement. 

Figure 11.5 shows the bonding in other molecular shapes with the tetrahedral electron-group arrangement. The trigonal pyramidal shape of NH3 arises when a lone pair fills one of the four sp orbitals of N, and the bent shape of H2O arises when lone pairs fill two of the sp orbitals of O. 

Figure 10.6 The three molecular shapes of the tetrahedral electron-group arrangement.

According to the VSEPR model developed in Chapter 9, an inner atom with a steric number of 4 adopts tetrahedral electron group geometry. This tetrahedral arrangement of four electron groups is very common, the only important exceptions being the hydrides of elements beyond the second row, such as H2 S and PH3. Thus,... 

Solution (a) For CH3OH. The electron-group arrangement is tetrahedral around both C and O atoms. Therefore, each central atom is sp hybridized. The C atom has four half-filled sp orbitals ... 

What type of central-atom orbital hybridization corresponds to eadi electron-group arrangement (a) trigonal planar, (b) octahedral (c) linear, (d) tetrahedral (e) trigonal bipyramidal ... 

The methyl carbanion, CH3, has bond angles close to that in a tetrahedral arrangement of atoms, 109°, indicating 4 electron groups around the central C atom and sp3 hybridization. The lone pair of electrons exerts significant repulsive force on the electrons in bonding orbitals and must be counted as an electron group. 

If we examine the other central atom, the oxygen with the attached hydrogen, we observe the presence of two lone pairs and two bonds. The presence of these pairs and bonds, which total four, means that the electron-group geometry is tetrahedral. This arrangement has sp3 4 5 6 hybridization. Since there are two lone pairs, the molecular geometry is bent. 

Step 3 The geometric arrangement of the electron groups is tetrahedral. Step 4 For 3 BPs and 1 LP, the molecular shape is trigonal pyramidal. 

The water molecule s electron group geometry, which is determined hy the arrangement of its four electron groups around the oxygen atom, is tetrahedral (Figure 12.7). 

The Lewis structure for H2O shows that the oxygen atom has four electron groups around it. The best way to get four things as far apart as possible is in a tetrahedral arrangement. 

Molecular Shapes with Four Electron Groups (Tetrahedral Arrangement)... 

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