It doesn't learn any different moves when holding a plate, it just changes its type according to the plate it's holding.
No, you do not need all of the plates to catch Arceus. You can use the plates to change Arceus' type, though. Arceus is only available by event (which has long since passed). You can also use an AR (action replay) to hack the game and get an Arceus, all without plates.
Level 100. Judgement's type depends on which plate Arceus is holding.
Arceus, because Arceus can switch types and it is known as the Pokemon who created the world. Arceus : Meteor level, got owned by "city-sized" meteor and lost all his plates, got defeated by Pokemon and cement, even with rage not able to break free, and oh, for a Pokemon who created Sinnoh, he sucks, he can't even destroy a "ruins" with his signature move, "Judgment." Even with full plates not powerful enough to withstand a "too powerful to block / absorb" meteor! Arceus isn't even smart in any way, not knowing even the effects of cement, which is created by "materials" he provided during his creation of Sinnoh...Pitiful! Dialga : Not able to stop time, as proven in last three movies, owned by Arceus who can't even destroy "ruins" as mentioned before, owned by Giratina, tied with Palkia, only able to send people back in time, but not itself... Palkia : Not as strong as Giratina, Arceus with Psychic attacks broke through Palkia's space "trap," able to shield moves but shield is useless even to planetary damage, "Judgment" Giratina : Predictible with Shadow Force, Aura Sphere did little damage, even if supereffective to Dialga....slow movement...moves easily dodged by Arceus, what else can I say?
Yes. Arceus is normal type. and with the plates he can change his type.
there is none
yes Arceus can learn aura sphere because it is the god of pokemon. Also Arceus can learn 529 moves out of 559 moves
no, arceus is a Pokemon that can learn a lot of moves, he can even learn fly but there are many moves that he cannot learn. the only Pokemon that can learn all moves is mew...
Arceus is not able to learn any move like Mew can. However Arceus is able to learn a large amount of moves from TMs making it a very versatile Pokemon.
Arceus cannot learn roar of time or spacial rend.
No. It is close to it being able to learn them all, however there are a number of moves that it can not learn.
Arceus does not require an item in order to actually learn Grass-type moves, however it can be given the Meadow Plate in order to boost the power of these moves by turning it into a Grass-type Pokemon.
The plates are items that can increase the power of different types of moves. But when you catch arceus, if you put different plates on him, his type and color will change according to the plate.
They power up certain moves and change Arceus's type/form!
if you give them to an arceus the arceus would change types, for example a flame plate would obviously make him a fire type! Plates also power up moves of their type.
only an event arceus knows roar of time. and pichu cant learn pain split and moves like that to... it realy sucks dont you think?!
The plates are not an optional part of the game, but they can power up certain Pokemon's moves and change the Type of Arceus and his exclusive move, Judgement.
If we are talking Game I don't know. Maybe Arceus since he can use a plate to use super effective moves against psychic type like mewtwo. If we are talking Anime Arceus. In the anime if Arceus has all life plates he is invulnerable.