If I understand your post, you want to go from a Gen 4 CPU to a Gen 2 CPU? That seems to be a step down in performance. But in any case it is not possible as the Gen 4 and Gen 2 CPUs use different socket types.
I want to know if intel core i5-2400 supported to my computer I am using dell optiplex 3020. I can also provide you the motherboard model: Dell 0WMJ54. Thank you for reading my problem please help me to solve this conclusion      
Can intel core i5-2400 supported on my pc