The element Niels Bohr predicted would have zirconium-like properties was hafnium.
Bohr’s developing model of the periodic table led him to predict the existence and chemical behavior of an undiscovered element in the zirconium group. The element was eventually identified as element 72 and named hafnium, from Hafnia, the Latin name for Copenhagen.
German-Danish scientists Dirk Coster and George de Hevesy announced the discovery of hafnium in 1923. They found it in zirconium minerals, where the new element had been difficult to separate and identify. Its discovery supported Bohr’s prediction about the placement of the missing element in the periodic table.
Hafnium is not the same as bohrium, the synthetic element later named in Bohr’s honor. Hafnium is element 72, while bohrium is element 107. The other options—protactinium, technetium, and rhenium—are different elements with separate discovery histories and do not fit Bohr’s zirconium-like prediction.