CBSE Class 12-science Answered

Dear Student

 

The radii of the trivalent ions decrease slightly as the atomic number increases. The reason is that whereas nuclear +ve charge goes on increasing as the atomic number increases, the  electronic cloud experiences more inside pull (as the charge on the nucleus increases), all electrons are pulled in closer to the nucleus due to the occurrence of incompletely filled anti-penultimate shell so that the radii of the trivalent-ions decrease slightly as the atomic number increases.

 

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