Predict the classification of krypton and elaborate on the reasoning. a) krypton is a metal and has full core electron shells, is highly chemically reactive, and located on the right. b) krypton is a noble gas and has a full valence electron shell, is chemically non-reactive, and located in group 8a. c) krypton is a nonmetal and has a nearly full valence electron shell, is chemically reactive, and located by group 18. d) krypton is a metalloid and has half-full core and valence electron shells, is chemically non-reactive, and located in group 10.