The most common isotope of gold has atomic number 79 and atomic mass number of 197. How many protons and neutrons does the gold nucleus contain? If the isotope is electrically neutral, how many electrons does it have? If it is triply ionized, how many electrons does it have?

In an atom, the relation between the subatomic particles of the atom are given as follows -

For a neutral atom,

Atomic number = number of protons = number of electrons,

Mass number = number of protons + number of neutrons,

Hence, from the given information of the question,

Atom = gold

Atomic number = 79

Mass number = 197

Therefore by using the above equations,

For neutral atom -

number of protons = 79

number of electrons = 79

Mass number = number of protons + number of neutrons,

197 = 79 + number of neutrons,

number of neutrons, = 118

In case of triple ionization,

the number of electrons will reduce by three, i. e.,

number of electrons = 79 - 3 = 76.