220 dryer outlet problem

This is probably going to be obvious to someone used to working with electrical appliances. I just bought a dryer for a house I'm moving into. It needed a cord, so I took a pic of the outlet and bought the cord that matched. I took it home and tried to plug into the outlet to check the fit. As it touched the outlet, there was a bang/spark and the right prong of the outlet was blackened and slightly damaged on the end. Is this a problem with the outlet, or was it just because the cord wasn't attached to anything? I'm scare to hook up the dryer now without knowing if there's something wrong.