1. The problem is to solve for the atomic number or properties related to Au, which is the chemical symbol for gold. 2. Au stands for gold in the periodic table, and its atomic number is 79. 3. The atomic number represents the number of protons in the nucleus of an atom. 4. For gold (Au), the atomic number is 79, meaning it has 79 protons. 5. The atomic mass of gold is approximately 197 u (atomic mass units), which includes protons and neutrons. 6. To find the number of neutrons, use the formula: $$\text{Neutrons} = \text{Atomic Mass} - \text{Atomic Number}$$ 7. Substituting values: $$197 - 79 = 118$$ 8. Therefore, gold has 79 protons and 118 neutrons. 9. This information helps understand the element's identity and properties in chemistry and physics.