What is the symmetry of a nonbonding sigma orbital?
There is no bond axis to rotate around. Instead, imagine a line from the atomic core through the center of the nonbonding orbitals electron density. If you rotate around this line, the nonbonding orbital looks the same no matter how far you rotate it. So, the orbital has spherical symmetry. 5.16 What are the geometries of second period hydrides? (a) We have seen these Lewis structures before: (b) There are four e- pairs around each of the central atoms in these molecules (some are bonding e-, some are non-bonding lone pairs). The arrangement of these e- pairs is tetrahedral, something that is obvious if you make the models. (c) The molecular geometries are found by the looking at the arrangement of atoms around the central atom. They are, respectively, tetrahedral, trigonal pyramidal, and bent. (d) The electron pair and molecular geometries are the same for methane. For the other two molecules, the geometries are not the same because of the presence of lone pairs. See Figure 5.10 for s
