No,
Get Beldum in the Massoutbreak evovle @ level 20 and into Metagross @ level 45
You will have to evolve a metang.
I suggest using the masterball.
no you can catch it. However you can trade Pokemon to get geodude and metagross on black and white!
Wait until there is a mass outbreak of Beldum after you get the nationaldex
In the giant chasm, you can catch them. however, i would recommend catching a metang instead, because metagross are extremely rare.
Yes you can always go back and fight nascour again in realagam tower and get metagross.
at the giant hall in the swirling grass
After beating the Elite Four, head to Steven's house in Mossdeep. In there, take the pokeball. The Pokeball will give you Beldum, which you will have to level up to Metagross.
Catch it from some rooms in indigo, as a beldum, train it, and it will slowly evolve...
Beat Evice With Pokemon Over 60's or you can beat evice with metagross lvl 70 metagross save metagross for machamp because metagross know's psychic or espeon lvl 70 because machamp know's earthquake and catch tyranitar with a master ball i think he is lvl 55
You cant, but you can catch it's pre-evolution: Beldum, in the Safari Zone.