11.Suppose you have the most abundant isotope of gold (Au). How many neutrons would it have?

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asked Feb 18, 2021 134k views

1 Answer

Arsibalt · Answer 1 · 2021-02-25T02:37:07+0000

Neutrons = 118

The elements in nature have several types of isotopes

Isotopes are elements that have the same Atomic Number (Proton)

Atomic mass is the average atomic mass of all its isotopes

The most abundant isotope of gold (Au) is isotope Au-197

So the atomic mass of Au = 197

and the atomic number of Au = 79

Atomic mass is the sum of protons and neutrons

Atomic Number (Z) = Atomic mass (A) - Neutrons

Neutrons = A - Z

So neutrons for Au-197 :

$\tt neutrons=197-79=118$