Answer: x = 2
The step by step is attached to this answer, hope it helped!
Answer:
The formula is

Step-by-step explanation:
hope this helps
The inverse of the equation is
4 electrons will be on the second energy level. Only 2 can go on the first energy level, and only 4 can go on the second energy level. There will be 1 electron on the 3rd energy level.