What property can be used to tell the difference between two minerals, if they have the same hardness?

When determining the shape of a molecule, it is important to draw a lewis dot structure first in order to see the total number a. electrons within the moleculeb. bonding and unshared pairs around central atomc. unshared pair within the molecule( i really need it )

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?