It depends on the species.
There are quite a few websites, for example http://bulbapedia.bulbagarden.net or http://serebii.net , that list information about Pokémon, including when they level up, so you can look up each species/family there.
Some Pokémon do not evolve at a certain level, but need other conditions, such as a high Happiness score or levelling up at a certain time of day and/or holding a certain item, but you can find that for any species of Pokémon individually if you look for it online.
Buizel evolve at level 26.
Arbok does not evolve
Rare candies only raise a pokemon's level. There are no pokemon that need a rare candy to evolve. That being said, using a rare candy may elevate a pokemon to the level required for evolution.
blastoise doesnt evolve.
They all evolve at different levels
Emolga does not evolve. I played Pokemon White also and it does not evolve. Some Pokemon do but this one does not evolve.
Be specific. What pokemon? ---------------------------------------- Most of them evolve at level 16 than level 36 :)
It evolves in Pokemon Diamond and Pokemon Pearl at Level 40.
Pikachu do not evolve by level. They evolve when a thunderstone is used on them.
Pokemon evolve at different levels so you never really know what level it is
It will evolve at level 48
the level they ussually evolve.
it will evolve at level 21
Many Pokemon evolve at certain levels. Some don't even evolve with level!
At level 16. if you don't know how to evolve Pokemon then go to your Pokemon box with your level 16 Charmander and press evolve.
Rephrase your question = What level does snorlax evolve on Pokemon diamond? =
The Pokemon cascoon will evolve into Dustox at level 10 =D