Which of the following statements best explains why nitrogen gas at STP is less dense than gas at STP?

Which of the following statements best explains why nitrogen gas at STP is less dense than  gas at STP?

	Because the  atoms are much more massive than the  molecules, they move more slowly and thus exert less upward force on the gas container and make the gas appear denser. The  atoms are larger than  molecules and thus take up a larger fraction of the space occupied by the gas. Because  is a noble gas, there is less tendency for the  atoms to repel one another, so they pack more densely in the gas state.  atoms have a higher mass than  molecules. Because both gases at STP have the same number of molecules per unit volume, the  gas must be denser.
Correct