When it comes to "watch the electrons dance" chemistry, superheavy elements are an upland meadow. They're expected to do things that smaller elements can't. But the focus of chemical thought seems to involve one of the most exotic environments in the universe. A conservative but reasonable guess puts the number of planets on which physicist-catalyzed nuclear reactions (PCNR) and chemist-mediated cooling (CMC) can occur at around 20 per Milky-Way sized galaxy. Fusion of large nuclei requires temperatures approaching a trillion Kelvin (1 Mev is roughly equivalent to 10^10 K). Only when such nuclei are cooled to less than 1000 K are such concepts as valence-shell chemistry meaningful.

Outside the lab, that almost never happens. The chemistry of superheavy elements is high-temperature chemistry, high-vacuum chemistry, ion-implantation chemistry, crystal growth chemistry, and not much more - unless the highly-stripped ions (most of them having a noble-gas electron structure) found in the outer layers of stars can interact. Oxygen is the predominant oxidizing agent, followed by sulfur. Phosphorous concentration is about 3 orders of magnitude down compared to oxygen, and everything else is rare. As a practical matter, the chemistry of superheavy elements is a matter of competition for oxygen and sulfur.

This is so because superheavy elements don't last long. Some recent calculations indicate that 293Cn has a half-life on the order of 1000 years. After 100000 years (100 half-lives), the concentration of 293Cn left in an initially-pure sample is well below the concentration of either At or Fr in the earth. Superheavy elements are synthesized when a neutron star forms (supernova) or disintegrates (merger), and are injected into space. Even if the diffuse remnant of either event hits a planet a mere 4 light-years away, the number of atoms injected into the planet will be twenty orders of magnitude less than the total number of atoms given off in the original explosion. Aside from the tiny fraction lost to solid bodies, all superheavy nuclei will end their lives in or on cosmic dust or as lone atoms.

It should also be noted that speculation about the appearance, density, etc of Fr, At, Lv, Tn, or Og (as well nearly everything with higher Z) is silly. A pure specimen big enough to see of any of them would be white - white as in incandescent plasma - and its density is extremely environment specific. (Density in the outgoing shock is high; density in the rarefaction wave behind it is low.)