This form of disorganization may not be the norm, but it is also not uncommon. It is likely due to one of two factors. One possibility is that it is symptomatic of an aspect of Attention-Deficit/Hyperactivity Disorder. Another possibility is that it represents a mild deficit in what are called executive functions. These are skills involved in mastering everyday tasks by inhibiting impulsive actions and sustaining goal-oriented behaviors, learning and otherwise. The various skills, organization being one of them, develop as the pre-frontal section of the frontal lobe of the brain develops. Your son is only seven, and it is expected that executive function skills will mature over the years. No seven year old possesses fully developed executive functions. For now, your son needs help in orienting himself to a task, and as he matures he will very likely grow in his capacity to handle this himself.