Revelation 11:15-19
The Seventh Trumpet
15The seventh angel sounded his trumpet, and there were loud voices in heaven, which said: “The kingdom of the world has become the kingdom of our Lord and of his Messiah, and he will reign for ever and ever.”
16And the twenty-four elders, who were seated on their thrones before God, fell on their faces and worshiped God, 17saying: “We give thanks to you, Lord God Almighty, the One who is and who was, because you have taken your great power and have begun to reign.
18The nations were angry, and your wrath has come.
The time has come for judging the dead, and for rewarding your servants the prophets and your people who revere your name, both great and small—and for destroying those who destroy the earth.”
19Then God’s temple in heaven was opened, and within his temple was seen the ark of his covenant. And there came flashes of lightning, rumblings, peals of thunder, an earthquake and a severe hailstorm.
From here we can see that the seventh trumpet (which is also the last trumpet) signifies the end of the age. The kingdom of this world has become the kingdom of our Lord and his Messiah and he shall reign for ever and ever.
The nations were angry for now had come the time for judging the nations on earth who are alive. (The dead outside of Christ are not resurrected until after the millennium at the Great White throne – this is the second resurrection or the pagan resurrection)
The judgment of the nations occurs at the Battle of Armageddon which is also part of the seventh trumpet.
The seventh trumpet is also the time when the believers dead and alive will be rewarded for the things that they have done in the body.
The last trumpet is of course the time when Christ returns and the time when the rapture and the first resurrection take place.
The seventh trumpet must span a period of time (possibly 75 days = 1335-1260) but the rapture occurs instantaneously, in a flash, in the twinkling of an eye, as soon as the trumpet sounds.
The seventh seal and the seventh trumpet appear to be synchronous or co-incident events as they are both connected to the rapture, the first resurrection and the second coming of Christ. They both seem to herald the end of the age.
The Seven Seals Trumpets and Bowls of Revelation 