You have to catch him/her.
Pikachu is found in Viridian Forest and at the Power Plant.
Pikachu can be caught at either the Viridian Forest, or the Power Plant.
You can't get pikachu in Pokemon colosseum you can see it but that's all, if you want pikachu you would have to trade one from firered, leafgreen, ruby, sapphire or emerald.
Raichu never evolves. Unless you meant Pikachu, which evolves into Raichu. Or Pichu, who isn't in Leafgreen but evolves into Pikachu, then Raichu.
In Pokemon Yellow, the only obtainable Pikachu is the one you receive from Professor Oak. You have to cheat or trade to obtain another Pikachu.
Caterpie, Weedle, Metapod, Kakuna, Pikachu.
Rare. Virdian Forest and Power Plant.
In Pokemon FireRed and LeafGreen, Pikachu learns Thunder at level 41. It can be sooner when given the TM Thunder.
Yes ! it is true depending on the trainer's ability to use Pikachu effectively.
Shadow Pikachu is not available in Pokémon LeafGreen. He is available in Pokémon Sapphire and Pokémon XD: Gale of Darkness.
While you can catch it in Viridian Forest, you can't get it as a starter. In Pokemon Yellow, an original Gameboy game, you can get Pikachu as your starter.
Abra, Exeggcute, Machop.
Venusaur,Rapidash,Gyarados,Pikachu,Pidgeot and Dragonite