Answer:
The number following the name of the element is the number of subatomic particles inside the nucleus of the atom. This means that it is the mass number of the isotope. The average atomic mass of the element is the sum of the products of the percentage abundance and mass number of the naturally occurring isotopes.
Since, the average atomic mass of the hydrogen is nearest to 1 then, the most abundant isotope should be hydrogen-1.
Atomic weights are weighted averages calculated by multiplying the relative abundance of each isotope by its atomic mass and then summing up all the products.
Chemical,when you light a match stick, you are starting a chain reaction of the substance chemical formula, making it a chemical change
