The lanthanoid contraction occurs when 4f orbitals are filled before the 5d series begins, resulting in a regular decrease in atomic radii. This phenomenon compensates for the expected increase in atomic size with increasing atomic number and causes the third ...

The decrease in ionic radius within a series occurs because, as the atomic number increases, a new electron enters a d orbital for each unit increase in nuclear charge. The less effective shielding of d electrons leads to increased electrostatic ...

Transition metals with very high enthalpy of atomization, corresponding to very high boiling points, tend to be noble in their reactions. The enthalpy maxima at about the middle of each series indicate that having one unpaired electron per d orbital ...

The high melting points of transition metals in the 3d, 4d, and 5d series are attributed to the involvement of a greater number of electrons from (n-1)d, in addition to the ns electrons, in the interatomic metallic bonding. The presence ...

Zn, Cd, Hg, and Mn are exceptions to displaying typical metallic properties among transition elements. Zn, Cd, and Hg lack typical metallic structures, while Mn deviates due to its anomalous values in terms of melting points.