Question

why is a practical capacitor always shown as an ideal capacitor in parallel to resistance while a practical inductor is an ideal inductor in series with a resistance

Answer 1

Because, in the case of the real capacitor, current will "leak" between the terminals, so the model will be that of a (usually) very low conductance in parallel with the ideal capacitor.

In the case of the coil, the wire itself adds resistance to the current, so overall pd is that of an ideal inductor and a low resistance in series.