2 Variation in
Atomic and
Ionic Sizes
of
Transition
Metals
�aH
�/kJ mol
–1
Rationalised 2023-24
94
Chemistry
increase in atomic size with increasing atomic number The net result
of the lanthanoid contraction is that the second and the third d series
exhibit similar radii (e g , Zr 160 pm, Hf 159 pm) and have very similar
physical and chemical properties much more than that expected on
the basis of usual family relationship