Take it to a jewlers to check it out but it should be able to get fixed! :)
platinum was not really thouht of being a use to people back in the past. It was thrown into the river to "ripen" but some of it would be lost.
Whose he
No, since Misty chose to stay back in Kanto, she will not be in Pokemon Platinum.
Does platinum change water back to hydrogen and oxygen using a current
No
Have an electabuzz and a ditto be in the daycare together come back after awhile and a guy will give you an egg when it hatches its an elekid.
Well you would have to be more serious with him and maybe he will start being srios!♥
They were bought back together by Director Vance he was looking for a mole that's why he split them up in the first place.
After The Lord of the Rings? No, he is in the Undying Lands.
In modern times a puzzle ring does not really serve a purpose but in the past they were used as wedding rings because if the wearer took it off in order to cheat on their spouse then they would be unable to put it back together again before being caught.
He probably wants to talk more about why you broke up with him and possibly wants to get back together.
That depends on your relationship.