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The elements Z (atomic number) = 117 and 120 have not yet been discovered. In which group would you place these elements?

I tried to write their electronic configurations but it was too tedious and I do not remember the Aufbau principle to that extent ($\ce{5g, 6f}$...).

Is there any quicker way to solve this question?

Gaurang Tandon
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GK A
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  • Till Uuo (atomic number=118 ) the places in periodic table ate known.So you start placing the 119th one in 1st group and so on so that you the shape of periodic table is not disturbed. But i am not sure – Pan Aug 26 '18 at 04:53
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    One way you can go about doing this is learning the number of elements present in each period. The first period has 2, the second and the third have 8 each, the fourth and the fifth have 18 each, the sixth and the seventh have 32 elements each. Since the noble gases are present at the end of the period, you can now calculate their atomic numbers which are - 2, 10, 18, 36, 54, 86 and 118 (2+8=10, 10+8=18, 18+18=36, 36+18=54, 54+32=86, 86+32=118). Now you can place Z-117 in the Halogen group(17) just before the noble gas, and 120 in the Alkaline earth metals group(2). – Parth Chauhan Aug 26 '18 at 06:42
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    117 has been made years ago, and it even has a name since 2015. – Karl Aug 26 '18 at 09:02
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    Ditto element 118. – Oscar Lanzi Aug 26 '18 at 09:38
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    Elements 119 and 120 should be more or less typical alkali and alkaline earth metals. But the increasingly important relativistic effects make things more complicated. There is actually a wikipedia article about elements 119 and beyond: https://en.wikipedia.org/wiki/Extended_periodic_table – Feodoran Aug 26 '18 at 11:02
  • Given : Atomic number z=117 Number of protons=117 electronic configuration is [Rn]5f¹⁴6d¹⁰7s²7p⁵ Belongs to group 17-- Halogen Family 11) atomic number =z=120 number of protons= 120 so, electronic configuration is [Uuo]8s² element belongs to group 2 ---Alkali earth family – Aryan Sep 16 '19 at 19:25
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    You would place Z = 120 in the second group, Alkali Earth Metals, as that element completely fills the 8s orbital. Z = 117 is Tennessine, which is a group 17 Halogen and has already been discovered. – JERRY_XLII Sep 17 '19 at 04:43

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