From what I've learned atoms with unpaired electrons are paramagnetic and those without are diamagnetic. Strontium has electron configuration of [Kr] 5s^2 so why is it paramagnetic?
Where did you get the information about para- / diamagnetism of the elements from. Are you sure they refer to isolated atoms (e.g. in the gas phase) and not to the metal? The magnetic properties of metals is a wholely different story.