Is strontium more metallic than sodium? If yes then why?

I got an MCQ in my examination, "Which one of the following is more metallic?" and the options were Sr, Na, Be or Aluminium. I know that sodium is more metallic than Be or Al but my mind stuck on strontium. 


-Strontium is the member of the fifth period and has greater number of shielding electrons than sodium (due to greater number of shells). This suggests that strontium should be more likeable to lose electrons. 


-But sodium has half filled valence "s" orbital while strontium has fully filled "s" orbital. This suggests that sodium is more likeable to lose its only valence electron.


-I've also looked for their first ionization energy values and they are almost comparable. 495.8 for Na and 549.5 for Sr. Why the I.E of sodium is a little bit less? (And should it be more metallic due to this?)


I've looked everywhere else on the internet but haven't found the answer. My question is, which of them is more metallic and why. 
And also are there any members of group IIA that are more metallic than any of the elements of group IA.


