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?

Explanation:

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 .

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

explanation: