Question

Why is iron a better conductor of electricity than zinc?

Answer 1

This is an excellent question, and one which made me think twice. It is arguably a manifestation of metallic bonding.

Explanation:

In metallic bonding, each metal atom is conceived to contribute 1 or more electrons to the metallic lattice to give, as commonly expressed, `"positive ions in a sea of electrons"`.

Such a picture of delocalized bonding rationalizes common metallic properties: hardness; non-molecularity; malleability; ductility ; and electrical conductivity. Because we have a partially filled `d` shell with the transition metal, the iron core should be able to commit more valence electrons to the lattice, and thus here the metallic bond is stronger.

In contrast, `Zn`, with a full `d` shell, can only contribute its two valence electrons to the metallic structure, resulting in lower melting and boiling points, and less(?) electrical conductivity.

Anyway, take all this with a gain of salt. There may be better answers available from some materials science guru.