Answer: Creative thinking
Explanation:
Creative thinking can be defined as the method by which a problem is solved with the help of thinking skills.
The thought that is present in mind is tries in the practical life so that the problem can be solved.
In given question Mandleev was trying to arrange elements in a logical way. He thought of arranging the elements based on the atomic weight.
This is an example of creative thinking in which the thinking is applied and a logical result came out of the thinking.