If you have an Intel MB and an AMD cpu they are not compatable.
If you have an AMD MB and an Intel cpu they are not compatable.
A MB has a list of supported cpu's either Intel or AMD and if a cpu that has the same pin count as the socket on the motherboard may not be compatable because it's not on the list of supported cpu's.
Inzone some older motherboard supported both amd and intel cpu's.
Socket 5 and 7 if I remember right....
There is technically nothing stopping either company from either using the others pin arrangement, however most major motherboard chipset manufacturers have agreements in place to prevent them from building a controller that will accept the other cpu makers processor on the same chipset.