Kottke links to a fearsomely difficult quiz
on the elements in the periodic table. Whilst you have a generous 15 minutes I scored only 30 out of a possible 118. In my defence I must admit that doing such a quiz in English is quite hard, as many of the elements' names are known to me in Dutch, whereas a lot of the abbreviations are from the Latin or Greek.
Take the quiz before reading further as there's spoilers ahead.
For instance I took about 5 minutes to remember that element 19 (K) is called Potassium in English. In Dutch it's Kalium, which makes a lot more sense. Na (11) is called Natrium in Dutch but Sodium in English. It also took me ages to get to the correct spelling for Fluorine (F, 9) as I kept trying Fluoride (it's simply Fluor in Dutch).
Don't even get me started on Tungsten (W, 74) which is Wolfraam in Dutch, or Mercury (Hg, 80) which is Kwik in Dutch, so that makes no sense in either language, although Kwikzilver and Quicksilver are phonetically similar.
Having said all that I am decidedly rusty: I missed out on quite a few obvious ones: Calcium, Silver, Gold, Arsenic, Cesium, Argon, Krypton to name a few. I did know Ununhexium, Ununseptium and a few of their close brothers but that's because their names are rather silly and once you know one chances are you know a few more.
I wonder if the quiz would be significantly easier if you just had to name the short periodic element name. But that might be a bit too easy perhaps. Although remembering Ag for Silver and Au for Gold would test your brain in a different direction.