Nucleus is present at the centre of atom. It contains protons and neutrons. It is very small as compared to the atom.
The movement of gases through pinhole is called effusion and the effusion rate indirectly proportional to the molar mass of gas
The lighter mass gas effuses faster than the heavier one
so He(g) will escapes faster and it will move with higher average speed because it has less mass than Ne(g)
