Covalent Radius

Covalent Radius

Covalent radius increases sharply between carbon and silicon — the first two members — but the further increase from silicon down through germanium, tin and lead is comparatively small. This flattening-out in the lower half of the group is attributed to the completely filled d orbitals (and, for lead, f orbitals) present in the inner cores of the heavier atoms; these filled inner subshells shield the growing nuc …