Question
How do atomic radius vary in a period and in a group? How do you explain the variation?
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Answer
Atomic radius increases down the group and decreases across the period. This is due to the continuous increase in the number of electronic shells or orbit numbers in the structure of atoms of the elements down the group.
From left to right across a period atomic radii generally decrease due to an increase in effective nuclear charge.
From left to right across a period atomic radii generally decrease due to an increase in effective nuclear charge.
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