Jonas's assignment was unique and special; it wasn't a typical job like his classmates were getting. They skipped him because they needed to explain a little bit more about his job, and because it was a somewhat historic event since they only choose a new Receiver once in a lifetime or so. When Jonas got his assignment, they apologized for confusing him, and explained that he was being given a very special job. They talked about how he had been specifically chosen for this job because they knew his talents and personality would be a good match for it, etc. So his assignment took a little longer than the others, and required a little more explanation. Instead of just throwing it in with the rest of the assignments, they skipped his number and kept his assignment until the end.
Jonas' job was the most important and the best, so they had to save it for last.
Jonas's assignment was unique. the Community of the Elders had to give an explanation about his special job as the new reciever of memories.
the reasean that his number had gotten skipped was because he got chosen to be the new giver, and also that the lady that was saying the numbers forgot to read his out loud.
Jonas was skipped because he got picked.