Zusammenfassung der Ressource
Shapes Of
Molecules
- Molecules with lone pairs
- Pyramidal
- These molecules have 1 lone pair and 3
bonding pairs of electrons
- Examples are: Ammonia(NH3) - Bond angle of 107 degrees
- Non-Linear/Bent
- These molecules have 2 lone pairs and 2 bonding
pairs of electrons
- Examples are: Water(H2O) - Bond angle of 104.5 degrees
- If a molecule is tetrahedral, 1 lone pair
will make it pyramidal
- Adding another lone pair to this will
result in a non-linear/bent shape
- A lone pair of electrons is more electron
dense than a bonded pair
- As such, each lone pair reduces the bond angle by
about 2.5 degrees
- Molecules without lone pairs
- Linear
- These molecules have 2 bonding pairs of electrons
- Examples are: H2 or CO2 - Bond angle of 180 degrees
- Trigonal Planar
- These molecules have 3 bonding pairs of electrons
- Examples are: BF3 - Bond angle of 120 degrees
- Trigonal Bipyramid
- These molecules have 5 bonding pairs of electrons
- Examples are: PCl5 - Bond angles of 90 and 120 degrees
- The angle between the vertical bond and horizontal
bond is 90 degrees. However, the angle between
each horizontal bond is 120 degrees
- Octahedral
- These molecules have 6 bonding pairs of electrons
- Examples are: SF6 - Bond angle of 90 degrees
- Tetrahedral
- These molecule have 4 bonding pairs of electrons
- Examples are: Methane - CH4 - Bond angle of 109.5 degrees
- Shapes of ions
- The principles about molecular shapes can be applied to ionic shapes
- As such in the example of an ammonium ion - NH4,
the shape is tetrahedral
- Thus meaning that it has 4 bonding pairs of electrons
- However, it will also need to be surrounded
by square brackets and have the displayed
charge as it is an ionic molecule