Mendeleev's realized that physical and chemical properties of an elements are coordinated with atomic mass of the elements so he has sequences the elements on per basis of atomic mass A
when it goes from cloud to rain/back to earth in the form of rain
answer: the rate of diffusion increases with increase in temperature.
increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.
generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.