Salient features of series combination :
The net resistance of the combination is equal to the algebraic sum of the resistances of the individual resistor.
The current flowing through each resistor is the same.
The voltage applied across the series combination of resistors is equal to the sum of potential differences across the individual resistors.
Salient features of parallel combination
The reciprocal of the net resistance of the combination is equal to the sum of the reciprocal of the resistances of the individual resistors.
Different amount of current flows through each resistor.
The potential difference across each resistor is equal to the voltage applied across the combination.