Why is the parasitic inductance placed in series with the resistance in the treatment of a real resistance?
The inductance must be in series because if it were in parallel with the resistor then the dc resistance would always be \$0 \Omega\$.

The capacitor must be in parallel because if it were in series the dc resistance would always be \$\infty \Omega\$.

These elements are where they are because the inductance tends to increase the impedance at high frequency while the capacitance tends to decrease the impedance at high frequency.