<span>Mass number is the number of protons and neutrons in an atom, and it tells us about the mass of the atom in amu, or atomic mass units. Atomic mass is the average mass of all the isotopes of a certain type.</span>
<span>Mass number found on the periodic table</span>
There are many ways to test and identify metal. The easiest way is observing its color. Also how reflective it is. Other ways would be boiling point, melting point, density, or conductivity of the metal.
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The answer is A. use casual, friendly conversation.
I think that it is qualitative data
