Question #d4706

2 Answers
Dec 5, 2017

Gold-197 has 118 neutrons.


Gold-197 has 118 neutrons. This is determined by subtracting the atomic number from the mass number.
197 amu-79= 118

The atomic weight or also known as the atomic mass have a fraction(decimal value) due to the average masses of the isotopes of the element. The mass number represents only the total of protons and electron of one atom of an element.

The atomic number represents the number of protons.

Thus, the difference of mass number - atomic number = number of neutrons.

Dec 5, 2017



Gold (Au) has an atomic number of 79, meaning that it has 79 protons.

The Relative Atomic Mass of gold is 197. 197 - 79 = 118 neutrons.