In ceramic capacitors the dielectric is a thin layer of ceramic and both plates are metal foil. These capacitors are unpolarized. These capacitors have negligible internal inductance or resistance.
In electrolytic capacitors the dielectric is an ultra thin layer of corrosion on the surface of a metal foil plate and the other plate is an electrolyte paste. These capacitors are polarized and if connected backwards are likely to explode. These capacitors have significant internal inductance, making them bad filters of noise in the MHz range and above which requires ceramic capacitors.
