1. The problem statement, all variables and given/known data For the same kind of atoms, if a solid is formed from a gas, is the susceptibility increased or decreased compared to the gas phase ? Why ? 2. Relevant equations Susceptibility of a gas is given as χ=N/V * α where N/V is average particle density and α is the atomic polarizability. 3. The attempt at a solution At first sight, since N/V would increase with solid formation the susceptibility would also increase. But I doubt that this is a plausible answer.