Yes it can evolve into Espeon during the day [with maximum friendship] or Umbreon during the night [with maximum friendship]. It can also evolve into Flareon, Vaporeon, and Jolteon with a Fire, Water, or Thunder Stone, respectively.
you can evolve pikachu into Raichu and Eevee into Jolteon
You can't.
To evolve Eevee into Espeon in Pokemon Emerald you need to raise it's happiness to max and level it up during daytime. To raise happiness you can keep the Eevee in your team for a while and fully healed up it should eventually reach max happiness to evolve in the daytime.
You can't naturally obtain jolteon in emerald. First you would have to get an eevee. Unlike other games an eevee isn't given to you. Trade with a friend to get an eevee or jolteon. Keep in mind you need a thunder stone to evolve eevee
Vulpix -> Ninetales Growlith -> Arcanine Eevee -> Flareon
Trade it to ruby,sapphire or emerald have them evolve your evee at night then give it back to leafgreen.
No you cannot get eevee in emerald, but you can get it in sapphire.
The Pokemon that evolve using a water stone: Eevee Starmie Lombre Poliwhirl, too...
Level up an Eevee with full happiness at nighttime (after 6pm)
an eevee, if given a water stone, will evolve into a vaporeon. sorry, but im not sure where you can find an eevee..
To get an Umbreon, you have to trade your Eevee to Pokemon Ruby, Sapphire, or Emerald, because there needs to be time if you're going to evolve Eevee into Umbreon. Keep Eevee with you until its happiness is at its highest, then evolve it with a moonstone WHEN IT IS NIGHT ACCORDING TO THE GAME CLOCK.
Eevee EvolutionYou can use it to evolve eevee into vaporeon. That's really optional though. cause you have to trade an eevee into the game. on ruby, you don't really need it though. on sapphire and emerald, its used to evolve lombre to ludicolo.