For 10 points, name this element that along with hydrogen is found in water.
One atom of this element is found in a prototypic furan and an atom of this element forms the bridge in an ether. The liquid form of one of its allotropes is paramagnetic. Reactive species of this element are potent free radicals. It is found with silicon in quartz. Another allotrope of this element absorbs UV radiation. It has atomic weight 16. Rust is a combination of iron and this. For 10 points, name this element that along with hydrogen is found in water.
One atom of this element is found in a prototypic furan and an atom of this element forms the bridge in an ether.
{oxygen}