I have now read in the Wikipedia pages for Unbihexium, Unbinilium, and Copernicium that these elements will not behave similarly to their forebear because of “relativistic effects”. When I read about Rutherfordium, it too brings up the relativistic effects, but only to say that it compared well w...

What really is a normal mode? Maybe it's because of my teachers but I find it really abstract. I know that "numerically" corresponds to the eigenvectors of the equation $\ddot{X}= -M^{-1}KX$ with the solution of the form $Ae^{-iwt}$ already plugged in, but what is the physical meaning of those ei...