Some elements are missing, and others have no name but have an atomic number. (116) When will the table ever be complete? How do we know that it's not already complete?

sorry start the sentence

On the periodic table....

The table will be complete when scientists stop making new elements. It is complete now for elements that occur naturally

ok thanks

An arrangment of elements in columns based on a set of properties that repeat from row to row... is hat?

The periodic table of elements is a tabular arrangement of chemical elements, organized based on their atomic number, electron configuration, and recurring chemical properties. It currently consists of 118 confirmed elements, with the most recent addition being element 118, Oganesson, in 2016.

Element 116 mentioned in your question is Livermorium, which was officially recognized by the International Union of Pure and Applied Chemistry (IUPAC) in 2012.

As for the completeness of the periodic table, it is believed that there may be more elements beyond the currently known ones. However, the higher the atomic number, the more unstable and short-lived these synthetic elements become. This makes their identification and confirmation challenging, as they tend to decay rapidly.

To determine if the periodic table is complete or not, scientists conduct experiments involving nuclear reactions, particle accelerators, and other sophisticated methods. These experiments aim to create and observe new elements by synthesizing them through nuclear reactions. The process involves bombarding atomic nuclei with projectiles to create new, heavier elements. By carefully studying the resulting decay products and their properties, scientists can gather evidence for the existence and characteristics of these elements.

Since the last confirmed element, Oganesson (118), was added to the periodic table in 2016, it is possible that more elements could be discovered and added in the future. However, the unstable nature of heavy synthetic elements makes their existence challenging to confirm and study in sufficient detail.

In summary, the periodic table is continually expanding as scientists discover and confirm new elements. Progress towards completing the table is an ongoing process, with researchers constantly pushing the boundaries of scientific knowledge and technology to uncover new elements.