The last few levels of SpaceChem introduces you to a number of 'unidentified elements', contained in an errata to your Periodic Table, labeled with the Greek characters Θ Ω Σ and Δ, or, Theta, Omega, Sigma and Delta. The Table contains no information on these elements - they have ? atomic number, and are allowed ? number of maximum bonds - other than the fact that they exist, and will be used in reactions.
What are the actual properties of these elements that we can tease out using the reactors? What will happen when we try to fuse, bond and split these elements?