In
transition state all the three C-H bonds are in the same plane and the
attacking and leaving nucleophiles are partially attached to the
carbon As the attacking nucleophile approaches closer to the carbon,
C-H bonds still keep on moving in the same direction till the attacking
nucleophile attaches to carbon and leaving group leaves the carbon As a result configuration is inverted, the configuration (See box) of
carbon atom under attack inverts in much the same way as an
umbrella is turned inside out when caught in a strong wind This
process is called as inversion of configuration