For a given Period, which is the smallest atom?

1 Answer
Jul 19, 2017


The inert gases are in fact the SMALLEST atoms of their respective Periods.


Do these data support the opening statement?

Units of #"picometre"-=1xx10^-12*m# are quoted............


And as we face the Table, atomic size DECREASES across the Period from right to left, and INCREASES down a Group, a column of the Periodic Table.

The Periodic decrease is a consequence of electronic structure. Incomplete electron shells shield the nuclear charge very ineffectively. Across the Period, #Z# wins, i.e. #"nucular charge"# wins. Down a Group, shielding by other electrons wins, and atomic radii increase markedly.