Period 3 element density and for its ability to resist corrosion due to the phenomenon of passivation. Structural components made from aluminium and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials. The most useful compounds of aluminium, at least on a weight basis, are the oxides and sulfates. "Silicon" (symbol Si) is a tetravalent metalloid. It is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table. Controversy about silicon's character dates to
Si Prat and the other works traditionally attributed to Si Prat were not written by him, and that he probably did not exist as commonly told, this consensus has not spread far outside of academic circles. The general public remains familiar with the traditional version of the Si Prat story, thanks in part to its popularization by the Fine Arts Department and its inclusion in school curricula since the 1970s. But whether seen as a historical figure or a fictional creation, Si Prat is regarded as a symbol of creative genius, the great poet from an idealized period of literary flourishing. Si