9
$\begingroup$

Is the shorthand electron configuration of $\ce{Br-}$ just $\ce{[Kr]}$?

Also what about $\ce{Ca^2+}$—is it just $\ce{[Ar]}$? And, is $\ce{Na+}$ just $\ce{[Ne]}$?

$\endgroup$
  • $\begingroup$ I meant is Na+ just [Ne] $\endgroup$ – Karis Mar 18 '18 at 18:39
  • 1
    $\begingroup$ Welcome to Chem.SE! I edited the post to reflect your change; you could have edited it yourself, though -- see the 'edit' link in gray at the bottom-left of your post. Please take a look at the tour and help center for more information about our site and community. $\endgroup$ – hBy2Py Mar 18 '18 at 19:53
10
$\begingroup$

You could render bromide ion that way. But the outermost electrons in the "krypton core" are potentially reactive, valence electrons; therefore $\text{[Kr]}$ is not an accurate description of how the electrons really act. Only the argon core acts like a noble gas, so you are better off rendering the bromide ion as $\text{[Ar]3d}^{10}\text{4s}^2\text{4p}^6$.

Cations stripped to the noble gas core, however, really are stripped to unreactive electrons, so calcium ion can accurately be rendered as $\text{[Ar]}$.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.