Which is a characteristic of mixtures? they are chemically bonded together. they can be classified as pure substances. they have fixed ratios between their components. they can be separated by physical processes.

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.