Read the given passage and answer the questionsthat follow : Fluorine and chlorine are fairly abundant while bromine and iodine less so. Fluorine is present mainly as insoluble fluorides [fluorspar, CaF_2, crylolite Na_3AlF_6, and fluoroapatite 3Ca_3(PO_4)2. CaF2] and small quantities are present in soil, river water plants and bones and teeth of animals. Sea water contains chlorides, bromides and iodides of sodium, potassium, magnesium and calcium, but is mainly sodium chloride solution (2.5% by mass). The deposits of dried up seas contain these compounds, for example, sodium chloride and carnallite,KCl.MgCl_2.6H_2O. Certain forms of marine life contain iodine in their systems, various seaweeds, for example, contain upto 0.5% of iodine and Chile saltpetre contains upto 0.2% of sodium iodate. Tennessine is a synthetic radioactive element. Its symbol is Ts, atomic number 117, atomic mass 294 and electronic configuration [Rn]5f^(14) 6d^(10) 7s^(2) 7p^(5). Name the last element of Group 17, its atomic mass and electronic configuration.