PART A: The element Si belongs to IVA group. Therefore, four electrons present in the outermost shell. Hence the condensed electron configuration of Si is [Ne] 3s23p2. PART B: The s orbital is completely filled and there are two electrons present in p-orbital. Therefore, the number of unpaired electrons of Si is 2 PART C: The atomic number of Zn is 30 and it belongs to IIB group. Therefore, the condensed electron configuration of Zn is [Ar] 4s23d10. PART D: All orbitals of Zn completely filled with electrons. Therefore, there are no unpaired electrons. PART E: The atomic number of Zr is 40 and it belongs to IVB group. This element is present after third element of Kr in periodic table. Hence the condensed electron configuration of Zr is [Kr] 5s24d2. PART F: The s orbital is completely with electrons and there are two electrons present in the d orbital. Therefore, the number of unpaired electrons of Zr is 2 PART G: The element Sn belongs to IVA group. Therefore, four electrons present in the outermost shell. Hence the condensed electron configuration of Sn is [Kr] 5s24d10 5p2. PART H: The s orbital and p orbital is completely filled. Therefore, there are two unpaired electrons in the Sn metal. PART I: The element Ba belongs to IIA group. Therefore, two electrons present in the s-orbital. Hence the condensed electron configuration of Ba is [Xe] 6s2. PART J: The outermost s- electron is completely filled. Therefore, there are no unpaired electrons present in Ba metal. PART K: The element Tl belongs to IIIA group. Therefore, the condensed electron configuration of Tl is [Xe] 4f14 5d10 6s2 6p1. PART L: The all orbitals are filled with electrons except Tl. Therefore, the number of unpaired electrons is 1 Solution PART A: The element Si belongs to IVA group. Therefore, four electrons present in the outermost shell. Hence the condensed electron configuration of Si is [Ne] 3s23p2. PART B: The s orbital is completely filled and there are two electrons present in p-orbital. Therefore, the number of unpaired electrons of Si is 2 PART C: The atomic number of Zn is 30 and it belongs to IIB group. Therefore, the condensed electron configuration of Zn is [Ar] 4s23d10. PART D: All orbitals of Zn completely filled with electrons. Therefore, there are no unpaired electrons. PART E: The atomic number of Zr is 40 and it belongs to IVB group. This element is present after third element of Kr in periodic table. Hence the condensed electron configuration of Zr is [Kr] 5s24d2. PART F: The s orbital is completely with electrons and there are two electrons present in the d orbital. Therefore, the number of unpaired electrons of Zr is 2 PART G: The element Sn belongs to IVA group. Therefore, four electrons present in the outermost shell. Hence the condensed electron configuration of Sn is [Kr] 5s24d10 5p2. PART H: The s orbital and p orbital is completely filled. Therefore, there are two unpaired electrons in the Sn metal. PART I: The element Ba belongs to IIA group. Th.