Four elements mendeleev studied when developing his periodic table

He found out that when they were organized in this way they form a repeating pattern that periodically repeated every seven elements. What are the four properties of elements studied by Mendeleev when developing his periodic table? Density, color, melting point/boiling point, and atomic mass were all used by Mendeleev.

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.