The statement that is/are true for the long form of the periodic Table is/are a. It reflects the sequence of filling the electrons in the order of sub-energy level s, p, d and f b. It helps to predict the stable valency states of the elements c. It reflects tends in physical and chemical properties of the elements d. It helps to predict the relative iconicity of the bond between any two elements

Sol. (a) Incorrect : Electrons are not filled in sub-energy levels s, p, d and f in the same sequence. (b) Correct : No. of valence shell electrons usually determine the stable valency state of an element. (c) Correct : Physical and chemical properties of elements are periodic function of atomic number which is the basis of modern, long form, of Periodic Table. (d) Correct : Realtive iconicity of the bond between any two elements is function of electronegativity difference of the bonded atoms which in turn has periodic trend in long form of Periodic Table.