Caption

Rhodium (Rh). Diagram of the nuclear composition and electron configuration of an atom of rhodium-103 (atomic number: 45), the most common isotope of this element. The nucleus consists of 45 protons (red) and 58 neutrons (blue). Rhodium is a transition metal in group 9, period 5, and the d-block of the periodic table. It has a melting point of 1964 degrees Celsius. The trends across the transition metals are due to electrons filling an inner d-subshell (here, within the 4th ring), shielding the outer electrons from the increasing nuclear charge.