Is this correct Japanese:?

not all of them work... well for example "ookii" would be "ookii desu" but "ookiku nai desu" one "i" drops in the second one. and not all adjs work in the second part of the sentence. another similar example would be "chiisai" (small). chiisai desu but chiisaku ni desu. one "i" drops. oh and for the first part, yes any noun can go in there. hon wa, hana wa,(flower) kabe wa (wall)....anything.hope this helps :)