Japan is an island nation located east of Eurasia, and 70% of the country is mountainous.
I don’t really understand the ある島国で part. My confusion is twofold:
Is the で particle here the conjunctive で?
What is the ある doing here? This really throws me off, because I can’t help but read it as “there exists an island country…” which of course makes no sense in this case.
I’d also be happy to see other examples of ある being used mid-sentence like this, without the meaning of “there exists”. I feel like I’ve seen that before but never really got it.
ユーラシア大陸の東にある島国 would be “An island country that is in East Eurasia”. “ユーラシア大陸の東にある” describes “島国”.
From the top of my head, I don’t have an example with ある, but an example of this grammar would be: ぼうしをかぶっているひと: a person that wears a hat, a person wearing a hat
Take with a grain of salt, but I think you’re trying to make a word-by-word translation of the english version and it doesn’t necessarily work this way.
If you want to say “A country in East Eurasia”, you could probably use の as in ユーラシア大陸の東の島国
I think it’s not a particle but the て-form of だ/です. You can find more details about using て-form to express “and” in a Tofugu article below, “て FORM FOR “AND”” section