Answer:
On the placement of hydrogen and helium in the periodic system
H1=1
He2=2
1) 2
2) 2
3) there are 2 atoms of hydrogen and 1 atom of oxygen, altogether is 3
4) subscript tells how many atoms of each element are present in the molecule
5) No, it is not balanced because the oxygen atom is not equal on both sides of the reactants and products. This wouldn’t be considered balanced as there are two oxygen atoms in the reactants section and only one oxygen on the products section.
It is:
2 H2 + O2 -> 2 H2O
The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary only in the number of neutrons they possess. Together, the number of protons and the number of neutrons determine an element's mass number.
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Answer:3.6 x 101 or 8.77 x 10-1