Question

how did the work of dmitri mendeleev differ from that of john newlands in the development of the periodic table?
mendeleev arranged the elements according to increasing atomic mass.
mendeleev predicted elements that would later be discovered.
mendeleev identified elements that had similar properties.
mendeleev organized elements into triads based on their properties.

Explanation:

Newlands arranged elements by atomic mass into "octaves" but did not leave gaps for undiscovered elements. Mendeleev also ordered elements by atomic mass, grouped similar properties, but uniquely left blank spaces and predicted the existence and properties of as-yet-undiscovered elements (like gallium and germanium). The other options are incorrect: both arranged by atomic mass, both identified similar property groups, and triads were the work of Döbereiner, not either scientist.

Answer:

Mendeleev predicted elements that would later be discovered.