Is it possible to place a satellite in geostationary orbit over the north pole?
No, a geostationary orbit must be in the plane of the Earth's equator. That way, by matching its orbital speed with the speed of a point on the equator, the moving satellite appears to be stationary over that point. Any other orbit would have the satellite appear to drift above and below the equator during the course of a day.
A geosynchronous orbit matches the Earth's rotational speed, but only allows a satellite to appear over the same spot once per day. Depending on your stretch of that definition, a satellite in a perfect polar orbit would pass over each pole once per day and might be called 'geosynchronous', but like the time of day at the poles the terminology becomes ambiguous.
Paul Walorski, B.A., Part-time Physics/Astronomy Instructor