A district spokesman says another 7th grader in the math class witnessed the shooting and told the teacher.
The shooting occurred just before noon Tuesday.
The victim was checked out in the nurse's office, but didn't have any injuries.
Philadelphia police arrested the suspected pellet gun shooter.
The district is investigating the incident and, at this point, doesn't know if there had been any problems between the two kids.
This is the second time in a week Philadelphia public school officials have had to deal with this type of incident.
Last Monday, Action News reported a fifth grader was accused of shooting another boy in the leg at Whittier Elementary in North Philadelphia.
The victim in that case was also not hurt.
Just like that incident last week, the student who shot the pellet gun in this school will also be up for expulsion.
The district says parents will be notified of the shooting and reminded that weapons of any type are not allowed in schools and backpacks need to be checked.
