O to evergrande city to beat the elite 4
...you beat the gym leaders
You need all eight badges and you have to have beaten the Elite Four in order to capture Rayquaza.
It really depends on the type of game that you have. If you have Ruby/Sapphire/Emerald, You must get the Eight Gym Badges of Hoenn. If you have Diamond/Pearl/Platinum, you will receive the Eight Gym Badges of Sinnoh. If you want HeartGold/SoulSilver/Gold/Silver/Crystal, you will get the Eight Gym Badges of Johto AND Kanto. If you have FireRed/LeafGreen/Red/Blue/Green (Japan Only)/Yellow (Pikachu Version), you will ONLY receive the Eight Gym Badges of KANTO.
you get all 8 gym badges
8.
The way you get Deoxys to stop sleeping in Pokemon Emerald is by collecting badges. Badges are earned through various challenges and achievements.
You can't
4
7
You can't trade badges in any Pokemon games. You have to earn them from the Gym leader.
You fight him after you get 4 gym badges
You fight him after you get 4 gym badges