If you Atom is arming and then it immediately flips over, or jumps around crazily, or just spins in place, your motors may be spinning incorrectly, or props may be on wrong.
Please use this diagram for motor/prop rotation:
If you are uncertain about prop rotations look for the letter 'R' on the prop after the numbers. This will indicate the ones that go on CW (Clockwise) motors.
Clockwise (CW) = Turns in the same direction as the hands of a clock
Counter-Clockwise (CCW) = Turns in the opposite direction of the hands on a clock.
If you are still having issues with your Atom behaving badly, open a ticket at https://rotorx.freshdesk.com