Mass of sodium :- 23 grams
Mass of Chlorine :- 35.5 grams
Mass of NaCl :- 58.5 grams
mass given :- 25 grams
moles :- 0.432 ( given mass/ ionic mass)

If an atom has 2 protons, then it must also have 2 electrons for there to be no charge. An extra electron will cause for you to have a negative charge, and if you have more protons than electrons, then you will have a positive charge. :)
The answer its O-H.........