Option C coz it should be ( CNH4)2. Hope i cleared your doubt
Iron has the chemical formula Fe from its Latin name, ferrum. Its atomic number is 26, and its molar mass is 55.845 grams per mole. It has a metallic gray color and is attracted to magnets. Iron is the second most-abundant metal on Earth.
Answer: The formula mass (formula weight) of a molecule is the sum of the atomic weights of the atoms in its empirical formula. The molecular mass (molecular weight) of a molecule is its average mass as calculated by adding together the atomic weights of the atoms in the molecular formula.
Hope this helps.... Stay safe and have a great weekend!!!!! :D
For it to be the same element it must contain the same number of protons