Out of #Sr, Ca, As, N#, which element has the smallest atomic radius?
The answer is
Got a Periodic Table? Of course you have, because you are doing your Chemistry homework, and a Periodic Table will be at hand! Anyway, ATOMIC radii DECREASE across a Period (i.e. a row as we look at the Table from LEFT to RIGHT), and INCREASE down a Group, a column of the Table.
We have Period 5
If I included oxygen, fluorine, and neon, could you make a prediction with respect to atomic size? The answer should be fairly clear.