You can't zoom to f/3.5 at 100mm on your lens, your lens will do at best f/5.6 at 105mm.
You can however get a shallow DOF effect quite easily, for example by shooting at f/5.6 at 105mm, with your subject quite close (say 6ft) and you background say 10ft behind the subject.
See this set of photos I took with a Nikon D70 (much older predecessor to the D7000!)
You can see the shot at f/2.8 has a shallower depth of field than at f/5.6, but at f/5.6 you can clearly see the subject in focus and the background blurred, you can even see that at f/8. (They aren't all sharp, I was on a tripod, long exposures, and caused the camera to move when I released the shutter, i used a 5s timer after that..!)
At f/5.6 at 200mm the effect is even more pronounced.
I'm sure at f/5.6 at 105mm you could do even better than I did, getting closer to the subject, and having the background further away.