VSEPR Worksheet
1) What is the main idea behind VSEPR theory?
2) For each of the following compounds, determine the molecular shapes and bond angles for the central atom. Draw the Lewis dot formula to begin with and use the VESPR Molecular Shape Chart to help you.
a) carbon tetrachloride (hint: tetra means "four")
b) BH3
c) silicon disulfide (hint: di means two)
d) C2H2
e) PF3 VSEPR Molecular Shape Table
The table below summarizes the molecular and electron-pair geometries for different combinations of bonding groups and nonbonding pairs of electrons on the central atom. Sn = Steric Number
n
/m
/ / / / /# of lone pair electrons on 'central' atom
/# of atoms bound to the 'central' atom
/Sn = m + n
/Electron-pair Geometry
/Molecular Geometry
/BondAngle
/Ex.
0
/2
/2
/linear
/Linear
/180
/BeH2
0
/3
/3
/trigonal planar
/trigonal planar
/120
/BH3
1
/2
/3
/trigonal planar
/bent
/less than 120
/SO2
0
/4
/4
/tetrahedral
/tetrahedral
/109.5
/CH4
1
/3
/4
/tetrahedral
/trigonal pyramidal
/107
/NH3
2
/2
/4
/tetrahedral
/bent
/105
/H2O
0
/5
/4
/trigonal bipyramidal
/trigonal pyramidal
/90, 120 and 180
/NH3
1
/4
/5
/trigonal bipyramidal
/seesaw
/90, 120 and 180
/SF4
2
/3
/5
/trigonal bipyramidal
/T-shaped
/90 and 180
/ClF3
3
/2
/5
/trigonal bipyramidal
/linear
/180
/PCl5
0
/6
/6
/octahedral
/octahedral
/90 and 180
/SF6
1
/5
/6
/octahedral
/square pyramidal
/90 and 180
/BrF5
2
/4
/6
/octahedral
/square planar
/90 and 180
/XeF4