45 Rh 102.91

Rhodium

Transition metal · Group 9 · Period 5

Rhodium (symbol Rh, atomic number 45) is a rare, reflective metal central to catalytic converters. It is classified as a transition metal and sits in group 9, period 5 of the periodic table.

Overview

Rhodium is the chemical element with atomic number 45 and the symbol Rh. With a standard atomic weight of 102.91, it is a transition metal. In the periodic table it occupies group 9 and period 5, and under standard conditions it is normally a solid. Rhodium is a rare, reflective metal central to catalytic converters.

Atomic structure

An atom of Rhodium has 45 protons in its nucleus and, when neutral, 45 electrons arranged in the configuration [Kr] 4d8 5s1. Its standard atomic weight of 102.91 reflects the natural mix of its stable isotopes.

Discovery and place in the table

Rhodium was discovered in 1803 by William Hyde Wollaston. It follows Ruthenium (Ru) and precedes Palladium (Pd) in order of atomic number.

Key properties of Rhodium
Atomic number 45
Symbol Rh
Atomic mass 102.91
Category Transition metal
Group 9
Period 5
Electron configuration [Kr] 4d8 5s1
Phase at STP Solid
Discovered 1803 (William Hyde Wollaston)