What chemical element is represented by 'Pb'?

Lead

What Broadway musical is based on the lives of the founding fathers of America, especially Alexander Hamilton? Who launched the first successful powered flight in 1903? Who famously advises Ross and Rachel, saying they were each other's 'lobster'? Which running back set an NFL single-season rushing yardage record in 1984 that still stands? In which state is Mount Rushmore located?