Answer:
Because it is more electronegative than nitrogen.
Explanation:
Oxygen has greater force of attraction between it's Molecules than nitrogen because it is more electronegative than nitrogen and this is because it has more slightly charged positive protons in it's electrons and thus make it slightly negative in it's nucleus. It has 8 electrons in it's nucleus compare to 7 electrons nitrogen has and this will make a bonding pair to occur in oxygen than nitrogen.
