Period 5

Period 5

Rubidium to xenon — the second transition series, featuring silver, tin and iodine.

Element count
18
First element
Z = 37
Last element
Z = 54

Period 5 mirrors the structure of period 4 with the 4d block. It contains everyday elements (silver, tin, iodine) and several electronic configuration anomalies (Mo, Ru, Rh, Pd, Ag) driven by the extra stability of half-filled and fully filled subshells.

Filling subshells
5s4d5p

18 elements