(N/A) The inductive effect is the permanent displacement of shared electron pairs along a carbon chain due to the difference in electronegativity between the carbon atom and an attached atom or group.
$1$. It is a permanent effect and operates through $\sigma$-bonds.
$2$. It decreases rapidly as the distance from the source of the effect increases.
$3$. Groups that withdraw electrons are called $-I$ groups (e.g.,$-Cl, -NO_2$),while groups that donate electrons are called $+I$ groups (e.g.,$-CH_3, -C_2H_5$).
Example: In $CH_3-CH_2-CH_2-Cl$,the chlorine atom is more electronegative than carbon. It pulls the shared electron pair of the $C-Cl$ bond towards itself,creating a partial negative charge $(\delta^-)$ on $Cl$ and a partial positive charge $(\delta^+)$ on the $C_1$ atom. This polarization is transmitted to $C_2$ $(\delta\delta^+)$ and $C_3$ $(\delta\delta\delta^+)$,but the effect weakens significantly with distance.