1. The problem statement, all variables and given/known data Hi, I've got the following problem: Calculate the spacing between atoms of an ideal gas at a temperature of 273K and a pressure of 1atm. 2. Relevant equations Mean free path equation: ʎ = 1 / 4(pi)(n)(σ²) 3. The attempt at a solution I first used the ideal gas equation PV =nRT to get n/V and thus I got 2.67 x 10^25 particles/m^3. But I dont know how I can find the radius of the atom. Am I using the wrong equation to get the spacing between atoms? Thanks!