if the zinc has a hardness on the mohs scale of 2.5 it is a physical properties. In addition to this zinc has a density of 7.13g/cm^3 at 25 degrees and it melt at 420 degrees. The physical properties of an element can be observed without changing the identity and composition of the substance.
Hardness on the Mohs scale is a physical rather than chemical property, because, in practice, it is measured through physical apparatus, rather than predicted from the chemical properties of the element.
