Identify the factors that guided mendeleev while classifying the elements.

Mendeleev was the Russian chemist who is responsible for devising the periodic table of the elements. He arranged all the known elements of that time with the elements that were not yet discovered in a tabular format. His table even predicted the chemical properties and the atomic masses of the unknown elements. The two factors that guided Mendeleev in this classification of the elements are as follows:

1. Organization of the elements in increasing order of their atomic mass.

2. Making groups of the similar elements together.

on island x the species needed to adapt because they were being subject to predators which didn't inhabit island y.