How many grams of the parent isotope are left in the sample after three half lives?

When preparing a tlc slide of a reference standard material (rsm), a solvent or mixture of solvents is used to dissolve the rsm and transfer it into the tlc plate. how does its polarity affects the rf of the rsm? the rf will increase depending of it polarity, but never decrease it does not affects it since the solvent evaporates before the insertion of the tlc slide in the jar a polar solvent will definitively reduce the retention factor a polar solvent will increase rf