Au79 = Gold. Au is the chemical symbol for gold, from the Latin Aurum, while 79 is the Atomic Number of 79 in the periodic table of elements.
Every atom of an element contains, in its normal state, an equal number of electrons and protons, each equal to its number in the periodic table, so each gold atom contains 79 protons and 79 electrons.
There is one stable isotope of gold, 197Au, so named because its atomic weight of 196.96655 approximates to 197 to the nearest integer. It contains 119 neutrons.
Unstable (Radioactive) Isotopes
There are 18 radioisotopes (radionuclides) of gold with 195Au being the most stable with a half-life of 186 days. Because this is such a short half-life, none of these radioisotopes are to be found naturally occurring on earth. They are known to exist in stars, some can be created in laboratories, others can be predicted.
Further Information About Gold
Our gold page contains a near complete, concise information source of technical information about gold.
Au79 - The Atomic Number of Gold is 79