Depending on how much you weakend it, yes.
You may also need to put it to sleep or paralise or something!
------------UPDATE-------------
This was tested using an emulator and savestates:
It is 100% possible to catch Mew full hp using only a pokeball.
I believe I restarted the game close to 40 times before it went.
Hope this helps.
Yes. As long if the games are the very newewst. I'll give you a list of Pokemon Games that have Arceus.
List: Diamond, Pearl, Platinum, Heartgold, Soulsilver, Possibly Black & White
NO. You cannot capture Arceus in the Game. But you can capture him by transferring him from Diamond/Pearl. Or you can just simply hack/cheat the game by purchasing ActionReplay (Which is a hacking device) for 24.99 (I think).
It is certainly possible to capture Arceus with a Poke ball or any other type of ball. However, the more powerful the Pokémon the harder it will be.
just keep trying
Get him down to 1 hp, confuse him, and then paralyze him. Then you might be able to catch him with a poke ball if you hack.
3 or 0.4% throwing a poke ball at full health it's better to use a master ball.
Master Ball
To catch a pokemon, you require a Poke ball, which you can buy from a poke mart.
a master ball or you can make it go to sleep and make it have low health and catch it with a ultra ball
masterball
Get him down to 1 hp, confuse him, and then paralyze him. Then you might be able to catch him with a poke ball if you hack.
3 or 0.4% throwing a poke ball at full health it's better to use a master ball.
Yes. It is completely possible to catch Mewtwo with an ultra ball.
You can catch Mewtwo easily by using a Master Ball on it or by using an Ultra Ball on it after lowering its HP.
I prefer to use my Master Ball for Mewtwo, but at least use an Ultra Ball.
MasterBall
you catch it with a poke ball
master ball
You can probaly catch him with a ultra ball but I would use the master ball
with a poke ball
by throwing it