Inductive Effect is of two types-
Positive inductive effect (+I Effect)
The electron donating nature of atoms or group of atoms is called positive inductive effect. It is denoted by +I.
Examples-
-C(CH3)3, -CH(CH3)3, -CH2CH3, -CH3 etc.
Negative inductive effect (-I Effect)
The electron withdrawing nature of atoms or group of atoms is called negative inductive effect. It is denoted by -I.
Examples-
-NH3+, -NO2, -CN, -SO3H, -CHO, -CO, -COOH, -COCl, -CONH2, -X, -OH, -OR, -C6H5 etc.