Answer:
Helium has atomic mass 4.002602.
So the answer to yr question is helium.
The nonmetal elements have a negative charge.
It is necessary to make a logical system for naming compounds because there are so many of them and thinking of arbitrary random names for each one and then later remembering them all would be impossible. Also, they need to be all recognized and standardized for global use so as to have everyone use the same system.
The answer is 0.492 because there are 100 meters in a hectometer, and 49.2/100 is 0.492