• # question_answer 3) The elements Z = 117 and 120 have not yet been discovered. In which family/group would you place these elements and also give the electronic configuration in each case.

The last period, i.e. 7th period of the extended form of periodic table will have the element with atomic number 118 (Noble gas). Thus, the element 117 will belong to halogen group and seventh period. Its electronic configuration is: $[Rn]5{{f}^{14}}6{{d}^{10}}7{{s}^{2}}7{{p}^{5}}$ 7th period, 17th group The element with atomic number 120, will be placed in group 2 (alkaline earth metals) and will have the configuration $[Uuo]8{{s}^{2}}.$