He arranged the elements in the increasing order of Atomic Mass and repeating periodic properties.
He was able to work out the atomic mass of the missing elements, and so predict their properties. And when they were discovered, Mendeleev turned out to be right. For example, he predicted the properties of an undiscovered element that should fit below aluminium in his table. When this element, called gallium, was discovered in 1875, its properties were found to be close to Mendeleev's predictions. Two other predicted elements were later discovered, lending further credit to Mendeleev's table.
When it was discovered that Mendeleev's table was based on the wrong characteristic. He believed that it was the mass of the elements that affected their properties. It is, in fact, their atomic numbers
Atomic Mass.
The Mendeleev table, also known as the periodic table, was organized by atomic number, atomic mass, and chemical properties of elements. Mendeleev was able to predict the properties of missing elements based on the gaps in his table.
Mendeleev was able to predict the properties of the yet unknown element (Germanium) by the properties of the surrounding known elements on his periodic table of the elements. Predicting properties such as reactivity, density, atomic mass, etc., he knew where the undiscovered element would be placed.
Dmitri Mendeleev is generally credited, as he was able to predict the properties of elements which had not yet been discovered based on 'gaps' in his table. He ordered the known elements in terms of their atomic mass in 1869; elements are listed in order of increasing atomic number in the modern version.
Mendeleev arranged the known elements by increasing atomic mass and grouped elements with similar properties together. Gaps in the table indicated elements that were yet to be discovered. By observing the patterns in the properties of known elements within each group, Mendeleev was able to predict the properties of the undiscovered elements that would fill these gaps.
mendeleev arranged elements according to atomic mass. He was able to observe periodicity when arranged in this pattern.
Mendeleev arranged the elements in the periodic table according to their atomic masses.
Dmitri Mendeleev arranged the elements in his periodic table in order of increasing atomic mass and grouped elements with similar properties together. This arrangement helped him to identify periodic trends and predict the properties of undiscovered elements.
Independently by Dmitri Mendeleev and Lothar Meyer in 1869
Mendeleev listed the atomic weights and chemical properties of elements as he began to organize them. He noticed that elements with similar properties appeared at regular intervals when arranged by increasing atomic weight.