Silver metal. Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm. At wavelengths shorter than 450 nm, silver's reflectivity is inferior to that of aluminium and drops to zero near 310 nm. Very high electrical and thermal conductivity is common to the elements in group 11, because their single s electron is free and does not interact with the filled d subshell, as such interactions (which occur in the preceding transition metals) lower electron mobility. The electrical conductivity of silver is the greatest of all metals, greater even than copper, but it is not widely
Conductivity near the percolation threshold critical exponents we have the "correlation length", formula_10 formula_11 and the "percolation probability", P: formula_12 For the description of the electrical percolation, we identify the occupied bonds of the bond-percolation model with the metallic component having a conductivity formula_13. And the dielectric component with conductivity formula_14 corresponds to non-occupied bonds. We consider the two following well-known cases of a "conductor-insulator mixture" and a "superconductor–conductor mixture". In the case of a conductor-insulator mixture we have formula_15. This case describes the behaviour, if the percolation threshold is approached from above: formula_16 for formula_6 Below the percolation threshold we have no conductivity, because