Palladium, with the chemical symbol Pd, is a transition metal found in Group 10 of the periodic table. It has an atomic number of 46. To determine the number of valence electrons, we look at its electron configuration, which is [Kr] 4d10.
In general, the valence electrons are those electrons that are in the outermost shell, or energy level. For palladium, the highest principal energy level is the fourth shell, which contains the 4d subshell. However, palladium is unique because it has fully filled d-orbitals. Therefore, for practical purposes, we consider electrons in both the d and s subshells in the context of transition metals.
Palladium actually has 10 d-electrons and does not have any electrons in the 5s subshell. As a result, it can be somewhat counterintuitive, but palladium is treated as having 2 valence electrons when considering its transition metal behavior in bonding, despite its complete d-subshell.
In summary, while palladium has 10 electrons in the 4d subshell, it is typically regarded as having 2 valence electrons that are involved in chemical bonding.