Question #d871b

1 Answer
Feb 16, 2015

The #"2n"^2# formula tells you in principle what the maximum number of electrons in a shell can be; at this time, no known element can have more than 32 electrons in its outermost shell because that would imply that those electrons are a part of the g-block, which would place the element in period 8 of the periodic table.

The element currently belived to have the highest atomic number (although it is very unstable) is ununoctium. This man-made element has an atomic number of 118 and is located in group 18 (although it is belived to be a "noble solid", not a noble gas), period 7.

Its electron configuration is this - I'll use the noble gas shorthand notation

#"Uuo": ["Rn"] 5f^(14) 6d^(10) 7s^(2) 7p^(6)#

A heavier element would have its outermost electrons in the O shell, with its g-subshell holding at most 50 electrons. Since heavier elements have not yet been successfully synthesized, this theoretical value for the maximum number of electrons in the outermost shell remains, well, theoretical.

If you're interested in reading more on the extended period table, you can do so here: