Re: Are the particles of the rings of Saturn unsorted as to mass.

Ring particles range in size from dust to the size of a town. Particles that small do not affect Saturn gravitationally, being so much less massive than the planet. In this case, the particles' orbits are not dependent on their mass at all. This is true as a rule in the solar system. This rule holds right up through the orbits of all moons in the solar system (except Charon about Pluto) and the planets about the Sun.¹

What does affect orbits? Velocity... sort of. The velocity of a body in orbit is determined by three things: the semi-major axis of the orbit (this is just the radius for a circular orbit), the mass of the thing it's orbiting (Saturn for the rings) and eccentricity of the orbit (this is just a measurement of how circular or non-circular an orbit is). The eccentricity does not affect the average speed, but it does affect how fast a particle is going at a given point. The more eccentric the orbit, the more speed will vary at different times in the orbit. For a circular orbit, the speed is the same, although the direction that particle is moving changes. In Saturn's rings, eccentricities are practically zero, so the orbits are, for most purposes, zero.

The result of this is that all particles at the same distance from Saturn orbit together.

Since you seem curious about the sizes of the particles, I thought I would also share a little about that. The sizes vary, as mentioned above, but there are more of the smaller particles than the larger ones. Isaac Asimov used to call this his "law of the numerous smalls." In physical space, particles of all sizes are mixed together. Someone made this simulation of what this mix might look like if you got into the rings and looked around.

For more information on rings, try:
The Nine Planets' Saturn Page
A NASA site on rings
or
A rings page produced for extension classes here at CU-Boulder.

Hope this helps!

¹ Note: Jupiter and the other planets do make the Sun move slightly as they orbit. This is nearly unnoticable and does not really affect their orbits. However, if you were looking for a Jupiter type planet going around a distant star, this motion would clue you in that that star had a planet. And, indeed, this is that is used by planet hunters.