Your i5-2500K supports memory up to 1333 MHz at 1.5v as shown below:
The Gskill memory you have is rated at 1600 MHz so it does not seem to be compatible.
You may also try to reset the BIOS and update it.
Besides that, if there is a chance the socket in the motherboard has bent pins you may need to swap the motherboard or the processor with another one in order to determine the faulty component.
Turns out that upon further inspection, the pins on the motherboard socket are bent to heck and back. I am surprised I was able to get it working at all. I am sending it back for return today and purchasing a different one.
Thanks for your help~!