Answer:-
Electrons or Protons
Explanation:-
Atomic number (Z) is defined as:
>>“The total number of protons in the nucleus of an atom is called atomic number”. All atoms of an element have the same number of protons and electrons.
>>“The total number of protons in the nucleus or electrons revolving around the nucleus of an atom”.
Example:
For instance, Hydrogen has the Atomic number(Z) 1.
Helium has the atomic number 2.
Oxygen has the atomic number 8.
| Note | Atomic number is represented by “Z”. And some ppl don’t consider the 2nd definition it’s upto u to do both or the standard one.
The sun of the protons a D neutrons in the nucleus of an atom is called the ATOMIC MASS
Answer:
formula units of sodium chloride can be formed from 13.0 gram of ferric chloride.
Explanation:
Mass of ferric chloride = 13.0 g
Moles of ferric chloride = 
1 mole of ferric chloride has three moles of chloride ions.Then 0.08 moles of ferric chloride will have :
of chloride

1 mole of sodium ion reacts with 1 mole of chloride ion to form 1 mole of NaCl. Then 0.24 moles of chloride ion will give:
of NaCl
1 mole =
molecules/ atoms
Number of NaCl molecules in 0.24 moles :

formula units of sodium chloride can be formed from 13.0 gram of ferric chloride.