=>in very simple way<=
In case of opposition of current
>In case of resistor connected in any circuit we can say that its resistance.
>In another same way resistor+capacitor, resistor+inductor,R+L+C connected in any circuit we can say that its impedance.
Resistance(R)-
Opposition flow of current in registor this type of property is called resistance.
The unit is ohm.
Reactance(X)-
Reactance is the opposition of a circuit element to flow of current due to that elements capacitance and inductance.
The unit is also ohm.
So this effect(Reactance) due to inductor that's called inductive reactance.(XL)
And so this effect(Reactance) due to capacitor that's called capacitive reactance.(XC)
Impedance(Z)-
impedance is also the opposition of a circuit element to flow of current due to the resistance+capacitance, resistance+inductance,
Resistance +capacitance+ inductance.
The unit is also ohm.
You can see below this chart-
In this chart Impedance R+L+C
