The rest were scattered out among the nations. Genetics tests were done not long ago that demonstrated that the scattered Jews were connected in a high degree to the original ancient people. Just in case someone is going to try to say that the Palestinians are the true Jews I'm going to pop that bubble. Palestinians are Arabs from Jordan, Egypt, Lebanon, and Syria who showed up and claimed the land about 3 generations ago. Many of them had to rent from the Arab land owners who owned it. They were what you call squatters.
The Ancient Jews weren't always in Israel. Abraham was a nomad who went throughout the Middle East. Before Judaism flourished, civilizations in Mesopotamia, India and China rose up. For a time, the entire Jewish population was enslaved in Egypt. Jews claiming a territorial homeland in Israel is bogus--the human race originated in Africa anyway when some great apes evolved into homo sapiens. If you want to go that far back, Ancient Jews at one time lived in Africa as hairy humans before evolving into more civlized people.
First, Israel didn't exist before the 20th century. Israel was the name of the Jewish people themselves. Also, Jews were not always in the area that today is called Israel. They were exited in Babylon and Egypt for some of their history. Israel is their homeland, but they did not always stay there.