MCQ
From the following, identify least reactive element :
  • A
    $\ce{{ }_8 Y^{16}}$
  • $\ce{{ }_{10} Y^{20}}$
  • C
    $\ce{{ }_{11} Y^{23}}$
  • D
    $\ce{{ }_9 Y^{19}}$

Answer

Correct option: B.
$\ce{{ }_{10} Y^{20}}$
Element,$\ce{{ }_{10} Y^{20}}$ has the electronic configuration as $2, 8$ has completely filled valence shell.
So, it is least reactive.

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