Why does glucose have a lower rf value than fructose?

[DespicableMe]

Even though their molecular formulas are the same? Fructose is an isomer of glucose and they are both cyclic and have 5 carbons so I was wondering why fructose was higher on the TLC plate than glucose.
Thank you.

 

[Borek]

It is not about molecular formulas, it is about interactions between the molecule and the stationary phase. These interactions are extremely sensitive to the molecule structure, which is why chromatography is so efficient as a separation method.