'Artık' can be used to say both 'anymore' and 'no more'. Ki has a larger usage, it doesnt mean anything itself alone. It can be used as an adjective addition like 'yanımdaki kız'(the girl who is next to me). or as a conjunction meaning 'so that, that..' like 'ev o kadar büyük ki, içinde bir çok insan yaşayabilir'(the house is so big that so many people can live in it) i hope i could explain well :)