Why do the transition elements have higher enthalpies of atomization? In 3d series (Sc to Zn), which element has the lowest enthalpy of atomization and why?

The transition elements, also known as transition metals, exhibit higher enthalpies of atomization due to their unique electron configurations. These metals have partially filled d-orbitals, which allow for stronger metallic bonding. The presence of d-electrons contributes to a greater overlap between atomic orbitals, resulting in stronger bonds that require more energy to break apart.

Lowest Enthalpy of Atomization in the 3d Series

Within the 3d series, which includes elements from Scandium (Sc) to Zinc (Zn), the element with the lowest enthalpy of atomization is Zinc (Zn). This can be attributed to several factors:

• Electron Configuration: Zinc has a full d-subshell (3d¹⁰), leading to a more stable electronic structure.
• Bonding Characteristics: The fully filled d-orbitals in zinc do not contribute as effectively to metallic bonding compared to other transition metals with unpaired d-electrons.
• Atomic Size: Zinc's larger atomic radius compared to elements like Scandium and Iron results in weaker metallic bonds.

As a result, the combination of these factors makes zinc's enthalpy of atomization lower than that of its 3d series counterparts.