We don't know the precise number, but it was in the hundreds of thousands.
70 years.
Because of the Babylonian Captivity, Babylonia became the most important center of Jewish life during the Exile. The Jewish people survived in Babylon because the Babylonian policy allowed the Jews to settle in towns and villages along the Chebar River, which was an irrigation channel. The Jews were allowed to live together in communities; they were allowed to farm and perform other sorts of labor to earn income. Many Jews eventually became wealthy.
The Jews could be scattered in what is now Iraq.
There are two major periods when the Israelites were in captivity. The first was the captivity in Egypt under Pharaoh and the second was the Babylonian captivity. A third captivity could be considered the Northern Kingdom of Israel being carried off to Assyria - however, this was an apostate group and only children of God by race rather than by religion.
Very many prophets, most of whose names are not recorded (Talmud, Megillah 14a). Those whom we do know, include Nathan, Gad, Isaiah, Jeremiah, Ezekiel, Joel, Nachum, Zephaniah, Habakkuk, Haggai, Zechariah, and Malachi.See also:More about the Israelite prophets
The Babylonian exile is the name given to the period of time in The Bible where the Babylonians captured many of the Israeli people and made them slaves.
There are two questions here:How many people? It takes 10 people to hold a full service, so that's the minimum. The maximum is however many people will fit, which depends on the size of the room.When were the first synagogues designed? We know that, by the time the Gospels and letters of Paul were written, there were synagogues all over the Roman occupied Jewish world and also synagogues elsewhere in the eastern Roman empire, all the way to Rome. So synagogues were developed before that time. The institution of the synagogue may have emerged during the Babylonian captivity. The first purpose-built synagogue, that is, one that could claim to have been designed, was therefore some time between the Babylonian captivity and the time of Jesus.
The Persians, under Cyrus, announced that those who wanted to return were free to do so. Many had established themselves well in Babylon and did not return.
75 escaped. 50 were shot. All but two were shot or returned to captivity.
525,000 people died in Belzec Concentration Camp.
There were 10 tribes, but they weren't lost. What happened was, during the Babylonian captivity of 586 BCE, the 12 tribes of Israel were expelled from the land and sent to Assyria. After 70 years, 9½ of those 12 Tribes had just assimiliated into Babylonian society, leaving only 2½ tribes returning to Israel.
Miscellaneous Babylonian Inscriptions has 177 pages.