Assertion : The value of enthaply of atomisation is maximum at about the middle of each series.
Reason : There is one uparied electron per d-orbital and this results in stronger interatomic interaction.

Assertion: The metals of 4d and 5d greater entalpies of atomisation than the corresponding elements of the 3d series. Reason: The metal-metal bond in 4d and 5d series are stronger than those in the 3d series.

Assertion : In transition elements radii of 5d series are virtually the same as those of the corresponding members of 4d series. Reason : The filling of 4f orbitals before 5d orbitals results in regular decrease in atomic radii.

Assertion : In transition elements radii of 5d series are virtually the same as those of the corresponding members of 4d series. Reason : The filling of 4f orbitals before 5d orbitals results in regular decrease in atomic radii.

Assertion : In transition elements, radii of 5d series are virtually the same as those of the corresponding members of 4d series. Reason : The filling of 4f orbitals before 5d orbitals results in regular decrease in atomic radii.

Assertion : The maximum oxidation state of chromium in its compounds is +6. Reason : Chromium has only six electrons in ns and (n-1)d orbitals