- An element is identified by its number of protons
- Proton is a kind of subatomic particle
- So, an element is identified by the proton number

- An element is identified by the proton number
- Gold is a kind of element
- Therefore, gold element can be identified by its proton number

Hence, gold element can be identified by its proton number
Gold atoms can be identified based on the number of which subatomic particles?
- An element is identified by its number of protons 
- Gold is a kind of element 
- Proton is a kind of subatomic particle