It depends did you kill it run away? You get to catch it again if it killed you'. Tip: always save in front of a legenarie so that you can turn your game off if you lose!
Above the floor where articuno is sitting there are boulders you need to push them down the holes you can push them by using Strength. Once you do that you can surf to articuno!
Buy about 50 Ultra Balls. Get a Pokemon with a Sleep-inducing move such as Sleep Powder or Sing. If you have a Pokemon under level 50 with Electric or Fire-type moves, that will also work well in lowering Articuno's HP. Once the HP is down to red or a small amount of yellow, put Articuno asleep and chuck Ultra Balls like crazy. If it wakes up, put it back to sleep again. Eventually you'll catch it.
once you catch all the unown you will find them randomly
I think you can't because I tried it once and it replaced my Articuno and Rayquaza with bad eggs. The weird thing is though, I was able to send one of the eggs into battle and it was Lv 45 with all the attacks my Articuno had. I do not recommend trying the shiny cheat with the WPM until a solution is found. PS: I was using a GameBoy Advance, not an emulator.
No, you can catch them only once per game.
Above the floor where articuno is sitting there are boulders you need to push them down the holes you can push them by using Strength. Once you do that you can surf to articuno!
Head to the Seafoam Islands once you have won all 16 gym badges. Work your way through the cave using Strength to move boulders out of your path and defeating any trainers along the way. Once you have reached the end of the cave, exit and you will face the first legendary bird, Articuno. Battle Articuno and once you have weakened it, use a Dusk Ball to catch it.
You can get Articuno in Pokémon Red, Blue, Yellow, Platinum, HeartGold and SoulSilver, in Red, Blue, Yellow, HeartGold and SoulSilver, you can find Articuno residing in the Seafoam Islands. In Pokémon Platinum, Articuno starts roaming around the Sinnoh region once you've spoken to Professor Oak in his place in Eterna City after you have received the National Dex and beaten Cynthia.
Articuno's in the Seafoam Islands on the very bottom. You have to do the Boulder/Strength puzzle to get to it though. Of all the 3 legendary bird Pokemon Articuno was the easiest (for me) one to catch once you were battling it.(and if you stand at the right spot in one of the corners you can see part of Articuno if you can't figure the puzzle out. :)
Once you get to Articuno (you can find a map online), DO NOT USE YOUR MASTER BALL! Please! Okay, now that I've gotten that out of the way, the best possible thing to do is to save IMMEDIATELY before you battle Articuno. Then use a mild electric-type move (thundershock is good) to slowly bring down its HP. When it gets to the red level, put it to sleep (if its not already paralyzed by thundershock) and use ultra balls until you catch it. Which reminds me. Bring plenty of ultra balls (30? 40?). Good luck!
you can't
first, catch a Pokemon that knows hypnosis. Then raise it's level to at least 51. Go to articuno. Battle it and weaken it, but don't kill it. Once you've weakened it, switch to the Pokemon that knows hypnosis and use that move on the articuno. While it's asleep, you use an ultra ball on it. Try to buy at least 20 ultra balls because that's how i started when battling Articuno and it worked. If you have catched it with the ultra ball. Then, BAM! You got yourself an articuno.
no because you have already confronted them its just like any other special Pokemon you only get it once
You can only catch Lugia once, but you have two chances to cat it. The first time in the story and later on. So if you catch Lugia once already, he won't be there the second time.
Articuno will disappear once you defeat it in HeartGold however you can bring it back in its place within Seafoam Island by defeating the Elite 4 and Lance regardless of whether you've already defeated them or not. Defeating Lance will activate the regeneration process for any Pokémon such as Articuno that is either considered a Legendary or a one-off Pokémon such as Sudowoodo.
Buy about 50 Ultra Balls. Get a Pokemon with a Sleep-inducing move such as Sleep Powder or Sing. If you have a Pokemon under level 50 with Electric or Fire-type moves, that will also work well in lowering Articuno's HP. Once the HP is down to red or a small amount of yellow, put Articuno asleep and chuck Ultra Balls like crazy. If it wakes up, put it back to sleep again. Eventually you'll catch it.
once you catch all the unown you will find them randomly