The white boxes with atomic numbers 113 and 115 represent elements that have not yet been officially named or assigned specific symbols. These elements are part of the group known as "superheavy elements" or "transactinide elements" and are highly unstable, with very short half-lives.
Element 113 was officially discovered in 2004 by a team of Japanese scientists at RIKEN (the Institute of Physical and Chemical Research). It was temporarily named ununtrium (symbol: Uut), based on its placeholder name derived from the Latin and Greek words for the numbers 1-1-3.
Element 115 was also discovered by a team of Russian and American scientists in 2003. It was temporarily named ununpentium (symbol: Uup) following the same naming convention.
Since the discovery of these elements, further research and confirmation are typically required to assign permanent names and symbols. The International Union of Pure and Applied Chemistry (IUPAC) is responsible for officially approving the names proposed by the discoverers before they are widely accepted and added to the periodic table.