"At a temperature of fifteen degrees, mercury is liquid."
Translation:Při teplotě patnáct stupňů je rtuť tekutá.
Why is it wrong to say "...rtut je tekuta", instead of "...je rtut tekuta" in the end of the sentence?
But it though that was only for personal pronouns. It's a verb. And, in fact, you czech people say different things. I heard, for example "Je to skvele", in which "je" is clearly not in the second position. Is "Je to skvele" kind of an exception?
Eh, sorry for the confusion. I was referring to something else.
Despite all of its quirks, Czech is basically a S-V-O language. That's why je is placed second. The same applies when rtuť is placed at the beginning: Rtuť je při 15 stupních tekutá.
Now concerning the other second position rule you have mentioned. It's not only about personal pronouns. Those are clitics. Yes, some personal pronouns are clitics, but auxiliary verbs, and other pronouns and certain prepositions are clitics too. I suggest looking at some grammar reference.
Finally, regarding your second question. To je skvělé. is the neutral sentence (or an exclamation). Clearly, its pattern is S-V-O. Je to skvělé is more of a question (V-S-O), but I can imagine it being used for emphasis or as a reply to a question as well. Look at this dialogue: A: Je to skvělé? B: Ano, je to skvělé. A: Tak to je skvělé!
TL;DR: Czech is way too much complicated.
(And please give me some award for the most imaginative dialogue ever.)
WTF! Ok.. Where could I find information about cclitics in czech? I mean, I really have no way to find them. When I put "clitics in czech" in Google, the results are not really satisfying xD.
About "Je to skvele", I heard it specially when someone did or said something "skvele". As "Mohl jsi to udelat na konci?" "Ano!" "Je to skvele".
I don't know what TLDR means, but it remind me "trdlnik" xD
(And yes! Sure you have a lingot! ;))