The temporary IUPAC systematic symbol for the synthetic element 117 is Uus.

Explanation:
- The International Union of Pure and Applied Chemistry (IUPAC) is responsible for naming and symbolizing elements.
- Synthetic elements are those that are created in a laboratory and do not exist naturally on Earth.
- Element 117 is one such synthetic element that was officially recognized by the IUPAC in 2016.
- As per the IUPAC guidelines, temporary systematic symbols are assigned to newly discovered or synthesized elements until a permanent name and symbol are proposed and approved.
- The temporary systematic symbol for element 117, Uus, follows the naming convention for elements.
- The first letter, "U," represents the symbol of the actinide series element uranium, which is the closest element in the periodic table to element 117.
- The second letter, "u," signifies that element 117 is the first element in the U series of synthetic elements.
- The third letter, "s," is assigned based on the position of element 117 in the periodic table, following the pattern established for other elements.
- The temporary systematic symbol Uus is used in scientific literature and discussions to refer to element 117 until a permanent name and symbol are approved.
- It is important to note that the temporary systematic symbol is not the final name and symbol for the element.
- The IUPAC will eventually propose a permanent name and symbol for element 117 based on certain criteria, including historical, mythological, or geographical references.
- The process of proposing and approving a permanent name and symbol for a newly discovered element can take several years.