* What is the heaviest of the naturally occuring Noble gases?
* What is the lightest element of the ones below with an atomic symbol that is also a US state postal code?
* What is the lightest element with an atomic symbol not related to its English name?
* What was the first element to be produced artificially?
* What element is the most electronegative and reactive of all elements?
* What element's three isotopes have different names?
* What element is name after Copenhagen, Denmark?
* Which element has close to 10,000,000 known compounds?
* It was not a good idea to invest in this gas in the early 20th century. Its price went from $2500 per cu. ft. (1915) to 1.5 cents per cu. ft. (1940)
* There are currently how many periods on the periodic table?