Topic Details (Notes format)

Which element has the chemical symbol "Pb"?

Which Greek letter is often used to represent an angle in mathematics?

What is the center of an atom called, containing protons and neutrons?

Which element has the chemical symbol "Nb"?

Which element has the chemical symbol "At"?

Which element has the chemical symbol "Mg"?

Who discovered the polio vaccine?

Which element has the chemical symbol "Ge"?

Who discovered America in 1492?

Which region in northern Chile and southern Peru is famed for dryness and astronomical observatories?