Question

Which gas has properties that are most similar to those of an ideal gas?

Answer 1

N2
O2
HE
Xe

Answer 2

Why would He be more ideal than Xe?

Answer 3

Hey there. Ideal gases are suppose to have even kinetic energy, behave as small perfect spheres, provide even momentum in the container and exert the same pressure throughout the motion. additionally they should have no forces of attraction.
when we say forces of attraction it means the compound has to be as most unreactive as possible and Helium respects that because it its outermost shell there are 2 electrons, which obey octects rule, that states that when the outermost shell has 2 or 8 electrons, the atom is stable. plus, those 2 electrons of helium are in the s orbital, and this is perhaps the strongest orbital, because it is deep near the nucleus, providing a great nuclear effective charge, meaning, it shall be quite hard for the atom to lose its electrons.

Answer 4

But Xe has a valance orbital of 8, wouldn't that be stable as well?

Answer 5

and unreactive?

Answer 6

Yes, it will. but the complete 8 electrons end up in a p orbital, rather than an s one. As i said, the s orbital is deep near to the nucleus more than the p orbital is. even if you draw shells for both atoms, He outermost orbital is nearer to the nucleus than Xe is, making He more stable.

Answer 7

Got it, thank you

Answer 8

My Pleasure.