What do numbers in the same period of the periodic table have in common

How are isotopes of the same chemical element alike? how are they different?

How can parts of a solution be separated by chromatography?

The solubility of barium nitrate is 9.02 g/100 g h2o at 20°c. a 15.2 g sample of barium nitrate is added to 200.0 g of water at 20°c. is the solution saturated, unsaturated, or supersaturated? a. unsaturated b. saturated c. supersaturated