Is the distance of some $n^{th}$ shell ($n$ $\neq$ outermost shell) from the nucleus of an atom different for different elements?

If so, then how much is the difference or how could we calculate it?


Yes, the size* of the $n$-th shell will differ between elements. The reason is that the nuclear charge will shrink each shell as it goes up. Additional electrons cannot fully compensate this effect because they do not perfectly shield the core.

The difference can be measured (see below) or calculated using quantum chemistry with flexible basis sets. Results from the latter can be validated against X-ray spectroscopy. However, even the Bohr model will yield different radii for the first shell when increasing the nuclear charge.

*The definition of the size is not trivial. One can use the van-der-Waals radius, ionic radius or determine the isosphere that contains e.g. 90% of the electron probability density as long as one is consistent about it.

  • $\begingroup$ Thanks, got it! $\endgroup$ – GouravM Oct 22 '19 at 18:30

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.