The nature of oxides changes from acidic to basic as we move down Group 14.

1. CO₂ and SiO₂: Carbon and Silicon are non-metals, and their oxides ($CO_2$, $SiO_2$) are acidic in nature.
2. GeO₂: Germanium is a metalloid, and its oxide ($GeO_2$) is distinctly acidic, though less so than $SiO_2$.
3. SnO₂: Tin is a metal (with some non-metallic character), and its dioxide ($SnO_2$) is amphoteric. It reacts with both strong acids and strong bases.
4. General Trend: Oxides of elements in the center of the periodic table or transitional zones often exhibit amphoteric behavior [Source 80].