Snap Infractions

[Trenchman]

First time poster here entreating your assistance. I'm the parent of a middle school center who is eager to learn all that he can about playing the position. At the risk of being too general, what constitutes a snap infraction by the center? Does the center have additional "latitude" with respect to movement of the free arm or body prior to the snap (relative to other linemen)? If so, to what to degree? Thanks any and all!