Explain why chromium has a higher melting point than scandium or zinc.

Cr has a higher melting point than Sc or Zn because Cr has more unpaired electrons in its d-orbital. 

Cr has a higher melting point than Sc or Zn because Cr has fewer unpaired electrons in its d-orbital.

Cr has a higher melting point than Sc or Zn because Cr has a smaller atomic radius.

Cr has a higher melting point than Sc or Zn because Cr has a larger atomic radius.