Chapter 2 - Atoms, Molecules, and Ions - Exercises - Page 76: 65

(1) Eu (2) Sn

(1) Given that the ion contains 63 protons, 60 electrons and 88 neutrons. Thus the atomic number is 63 as there are 63 protons and from periodic table we can find that the required element is Europium denoted by the symbol Eu. There are 60 electrons i.e 3 electrons less than protons which indicates that it has +3 charge. (2) Given that the ion contains 50 protons, 48 electrons and 68 neutrons. Thus the atomic number is 50 as there are 50 protons and from periodic table we can find that the required element is Tin denoted by the symbol Sn. There are 48 electrons i.e two electrons less than protons which indicates that it has +2 charge.