11852 12 Four new elements have recently been added to the Periodic Table. The four elements are given below, along with their atomic numbers and the mass numbers of their most common isotope. element atomic number mass number nihonium 113 286 moscovium 115 289 tennessine 117 294 oganesson 118 294 (a) What is the meaning of the following terms? (i) Atomic number [1] (ii) Mass number [1] (iii) Isotopes [1] (b) State and explain which element has the most neutrons. [2] 11852 [Turn over (c) Suggest why tennessine is placed in Group VII of the Periodic Table. [1] (d) Erbium is a soft, silvery solid that tarnishes slowly in air. It is used in fibre optic cables. There are six known isotopes of erbium and its relative atomic mass is 167.26. (i) Define the term relative isotopic mass. [2] (ii) The table below gives the percentage abundances of six isotopes in the mass spectrum of erbium. relative isotopic mass 161.93 163.93 165.93 167.93 169.94 % abundance 0.14 1.60 33.50 22.87 26.98 14.91 Calculate the missing relative isotopic mass. [3]