Question

Lewis Dot Structures describe the connectivity of the atoms in a species. a) Determine the central atom (least electronegative) Hydrogen will not be a central atom. b) Draw the skeleton. c) Determine the total number of valence shell electrons d) Place the electrons around the terminal atoms to satisfy the octet rule (Be). Hydrogen ok with two electrons. If there are electrons left over then place them around the central atoms as lone pair electrons. Some atoms (period 3 and greater can have an expanded octet so ok to have more than eight) Ifall the electrons are used and the central atom does not satisfy the octet then you may have to use a double or triple bond. Boron is ok with three bonds. a. b. Count to make sure all the atoms satisfy the octet and you used all the valence electrons. e) Valence Shell Electron Pair Repulsion (VSEPR) Theory describes the three dimensional shape based on the regions of electron density (bonding or nonbonding regions) around the central atom. a) Start with the Lewis Dot Structure b) Count the regions of electron density around the central atom c) Determine the electronic geometry (takes into account all the electrons- bonding and nonbonding) d) Determine the molecular geometry (takes into account the atoms bonded to the central atom) Valence Bond Theory describes the bonding around the central atom. The atomic orbitals on the central atom hybridize to make new hybrid orbitals. Hybrid used Regions around central atom 2 linear 3 trigonal planar 4 tetrahedral 5 trigonal bipyramidal 6 octahedral sp spa sp3d sp3d2 1) Draw the Lewis Dot Structure, 2) Describe the electronic and molecular geometry and draw the Valence Shell Electron Pair Repulsion Theory (VSEPR) sketch, and 3) Describe the bonding and draw the Valence Bond sketch for the following: CH4 H20 OF2 Нао" PCls CH20 COz PCIs SF4 SiF62 No3 IFs XeF4 I3 VSEPR Example Molecular Angle geometry Regions Electronic around central geometry atom 180° N2 2 Linear TrigonalTrigonal120 planar BF3 planar (3bp) Bent (2bp 120 1nbp) NOz Tetrahedral Tetrahedral 109.5 (4bp) Pyramidal 3bp Inbp) 1095 Bent (2bp 2nbp) NH3

Answer 1

Bent

8- Cl

E9 c t S F