On Pokemon leaf green i am trying to catch Articuno and it is not working so well is there any way to make this easier?

Use a Master Ball. Put it to sleep and then make its health really low, then throw Ultra Balls at it. If it wakes up, Paralyze it. It often helps if the Pokemon you are trying to catch has a status condition (Sleep, Poison, etc.). Using the move False Swipe (which Scyther learns) lowers the foe Pokemon's health to 1 HP and no less. Ultra Balls have a higher catch rate, so use a lot of them. If you can, factor in some Time Balls.