I think the answer is a not sure tho hope u the answe
21.5010667479427 I goth this asnswer cause I divided I think that's how u do it
The velocity of the gas is inversely proportional to the square root of the molar mass of the gass. Heavier molecules tend to travel slow compared to light molecules. Among these, He has the lowest molar mass of 4 g/mol hence this element has the greatest velocity among all molecules given.
No. The number of a protons is not equal to it's atomic weight, instead it is equal to the 'atomic number'