Van der waal's attraction forces are caused by the newton's gravtional forces ,so the heavier the atom the stronger the attractive forces betwen its molecules and the denser the gas is !!

But Avogadro's law states that equal volumes of different gases contain the same number of molecules (or atoms if the gas is mono atomic )!!
How is it possible that (for example) a cubic centimeter of radon (222 atomic mass unit) with large attractive force and more density and a cubic centimeter of helium (4 atomic mass unit) that has weaker attractive forces contains the same no of molecules ?!

Question

Van der waal's attraction forces are caused by the newton's gravtional forces ,so the heavier the atom the stronger the attractive forces betwen its molecules and the denser the gas is !! 

But Avogadro's law states that equal volumes of different gases contain the same number of molecules (or atoms if the gas is mono atomic )!! 
How is it possible that (for example) a cubic centimeter of radon (222 atomic mass unit) with large attractive force and more density and a cubic  centimeter of helium (4 atomic mass unit) that has weaker attractive forces contains the same no of molecules ?!

gebooors · Answer

van der walks forces are involved with electromagnetic
Attraction or repulsion.

gebooors · Answer

Van der Waals forces, of course.

anonymous · Answer

how is it involved to atrraction and repulsion forces ?? ......i mean isn't the gravitional law applied on the atomic level ??

gebooors · Answer

On short distances, electromagnetic forces are stronger.
Gravitational forces are involved with Great masses.