(a) Based on the number of electrons, can you determine the identity of X? (b) Would the molecule be diamagnetic or paramagnetic? (c) Consider the π 2 p MOs of the molecule. ĩ.10 The diagram that follows shows the highest-energy occupied MOs of a neutral molecule CX, where element X is in the same row of the periodic table as C. ĩ.9 For each of these contour representations of molecular or-bitals, identify (a) the atomic orbitals ( s or p) used to construct the MO (b) the type of MO (σ or π), (c) whether the MO is bonding or antibonding, and (d) the locations of nodal planes. (a) What is the hybridization at each carbon atom in the molecule? (b) How many σ bonds are there in the molecule? (c) How many π bonds? (d) Identify all the 120° bond angles in the molecule. What type of hybrid orbital is produced in this hybridization? ĩ.7 The orbital diagram that follows presents the final step in the formation of hybrid orbitals by a silicon atom. (a) To what does an energy of zero correspond in this diagram? (b) According to the valence-bond model, why does the energy decrease as the Cl atoms move from a large separation to a smaller one? (c) What is the significance of the Cl-Cl distance at the minimum point in the plot? (d) Why does the energy rise at Cl-Cl distances less than that at the minimum point in the plot? (e) How can you estimate the bond strength of the Cl-Cl bond from the plot? ĩ.6 In the series SiF 4, PF 3, and SF 2, estimate the F-X-F bond angle in each case and explain your rationale. (a) Based on the structure, how many electron domains surround the C atom in this molecule? (b) Would the molecule have a nonzero dipole moment? (c) If the molecule is polar, in what direction will the overall dipole moment vector point in the molecule? ĩ.5 The following plot shows the potential energy of two Cl atoms as a function of the distance between them. ĩ.4 The molecule shown here is difluoromethane (CH 2F 2), which is used as a refrigerant called R-32. This formation of new hybrid orbital is possible by combining several types of orbitals (s,p,d and etc).CHEMISTRY THE CENTRAL SCIENCE 9 MOLECULAR GEOMETRY AND BONDING THEORIES EXERCISESĩ.1 A certain AB 4 molecule has a “seesaw” shape:įrom which of the fundamental geometries shown in Figure 9.3 could you remove one or more atoms to create a molecule having this seesaw shape? ĩ.2 (a) If these three balloons are all the same size, what angle is formed between the red one and the green one? (b) If additional air is added to the blue balloon so that it gets larger, what happens to the angle between the red and green balloons? (c) What aspect of the VSEPR model is illustrated by part (b)? ĩ.3 For each molecule (a)-(f), indicate how many different electron-domain geometries are consistent with the molecular geometry shown. However, two orbitals can not contian more than two atoms due to the maximum capacity it can hold.Īlso, because known atomic geometry can not be able to have effective overlap, atomic orbitals combine with each other and reconfigure themselves into a different configuration. Just like forming a molecule with lewis dot structure, bonds between atoms complete when two electrons share same orbital together.īond strength depends on the the amount of overlap since electrons are attracted to nuclei of both atoms, more electrons will pull more nuceli thus increase bond strength. According to this theory, bond will form whenġ) An orbital of one atom occupy another atom's orbital, known as overlap.Ģ) number of electrons in both orbital is adds up to no more than two. The Valence Bond thoery simply explains the bond formation just like lewis dot structure, but instead it explains the bonding in terms of covalent bond by quantum mechanics.
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