You have 5000 atoms of gold and 5000 atoms of silver. Which statement is true. You have the same mass of each.
You have the same number of moles of each.
Both are true.
Neither are true.

"You have the same number of moles of each." is the true statement.

The mass of Gold and Silver differ, so that first statement can't be true because the quantities are the same. Because a mole measures solely amounts, like a dozen does, you will have the same amount of moles if the quantities are the same.

D - for example, Potassium has 1 electron on its outer shell, whilst Chlorine has 7 electrons on its outer shell. Potassium loses one electron to Chlorine so that each of them have a full outer shell. This would form Potassium Chloride.