1) Anomalous pair of elements : Certain elements of highest atomic weights pre¬cede those with lower atomic weights.
Ex : Tellurium (At.wt. 127.6) precedes Iodine (at.wt. 126.9).
2) Dissimilar elements placed together : Elements with dissimilar properties were placed in same group as sub-group A and sub-group B.
Ex: 1) Alkali metals like Li, Na, K etc., of LA group have little resemblance with coinage metals like Cu, Ag, Au of IB group.
2) Cl is of VIIA group and 'Mn' is of VII B. But chlorine is a non-metal whereas Mn is metal.