Gold (Au) is a metallic chemical element with atomic number 79. The reason it has the element symbol Au is that it's called aurum in Latin.

Just like silver, which is in the same group in the periodic table, gold has a very long history of being considered valuable, and as a result it has been used as money for a very long time. While gold isn't used as currency today, central banks still keep some gold in their vaults. Gold is more rare than silver, and is therefore more expensive.

Gold is used both as an investment and in jewellery, but it also has some industrial applications such as electronic circuits.

Gold is resistant to corrosion and resistant to almost all acids, but it does dissolve in aqua regia, which is a mixture of nitric acid (HNO₃) and hydrochloric acid (HCl).

The only stable gold isotope is ¹⁹⁷Au, with 79 protons and 118 neutrons.