MCQ
An ion has $18$ electrons in the outermost shell, it is
  • $C{u^ + }$
  • B
    $T{h^{4 + }}$
  • C
    $C{s^ + }$
  • D
    ${K^ + }$

Answer

Correct option: A.
$C{u^ + }$
a
Atomic number of copper $Cu$ is $2 9 .$

Electronic configuration of copper $=2,8,18,1$

When copper loses one electron then it becomes a positive ion that is $Cu^+$.

No of electrons in ionic $Cu^+\,=$ atomic no. of copper $-$ no. of electrons lost

$=29-1=28$

Therefore electronic configuration of copper ion $Cu^+\, 2,8,18.$

This means that $Cu^+$ has $18$ electrons in its outermost shell.

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