The mass of substance which consists the equal number of particles as 12 grams of Carbon-12 is said to be mole.
For example:
The balanced chemical equation for production of water from hydrogen and oxygen is:
That means 2 moles of 
reacts with 1 mole of 
to give 2 moles of 
.
The given formula is 
.
Hence, 4 represents the number of moles in formula that is 4 moles of 
.
The number of atoms of sodium, 
in is:
The number of atoms of sulfur, 
in is:
The number of atoms of oxygen in, 
in is:
Its an atom, or molecule, [in which] the complete amount of electrons isn't equal to the complete amount of protons. (Giving the atom/molecule a positive or negative electrical charge).
If this is incorrect- I'm sorry! ^^;
The atomic number is made out of the number of protons and neutrons in an atom.
(Mark me brainliest!)
