7. (5 points) As shown in the figure, first place 4 black and 1 white, a total of 5 chess pieces on a circle. Then, place a white piece between two pieces of the same color, and a black piece between two pieces of different colors, and then remove the original 5 pieces. If this operation is repeated, the maximum number of white pieces among the 5 pieces on the circle is $\qquad$.
【Answer】Solution: From the above figure, it can be seen that for the case where 5 chess pieces are presented on the circle, the maximum number of white pieces on the circle can be 3.

Answer: Among the 5 chess pieces on the circle, there can be at most 3 white pieces.
Therefore, the answer is: 3.