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1. The atomic number refers to the element and how many electrons an atom may hold, the neutrons determine the isotope, an all together different matter that involves decay rates and sometimes the source of a number of atoms.
H2
No
hydrogen is odorless
Gas
hygrogen and oxygen
a couler less gas that burns easily and is the lightest element of the universe
Assuming you mean hydrogen, you could start with water (H2O).
8 electrons
16 electrons
20 electrons
6 electrons