What does the 2 represent inH2

dihydrogen monoxide. The 2 is the subscript for H symbolises the presence of 2 Hydrogen atoms.

Explanation:

If we want to represent two atoms of hydrogen, instead of writing H H, we write H2.

Explanation:

The subscript "2" means that two atoms of the element hydrogen have joined together to form a molecule. A subscript is only used when more than one atom is being represented. ... Some more common molecules and their chemical formula.

answer; /// the amount of material dissolved in a measure of liquid(concentration) the above statement is (true); /// good luck

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.