Hi, welcome. It sounds as if your software is broken.
Which version of Civ5 have you bought - Steam or AppStore?
If it's the Steam version, right click the Civ5 entry in your Steam library, select Properties -> Local Files, and Verify the local game cache. Steam should fix any corrupt files. If this doesn't work, try Deleting the local files. The next time you click on Play, it will download a fresh copy - be prepared for a wait.
If you have the AppStore version, I suggest deleting it and downloading it again from the AppStore.