If new elements are placed, then they would be appended in the Periodic Table. It won't disturb existing periodic table.
CO3 is not placed in periodic table. Only elements are arranged in periodic table.
Metals are placed at the left. Non-metals are placed at right in periodic table.
The periodic table is an array of various elements. Iodine is an element. Hence it finds it place on the periodic table.
Lanthanides and Actinides are placed separately as the properties of these elements is quite different from the elements in periodic table.
The periodic table contain all chemical elements, placed in a rational order.
All chemical elements are placed in the periodic table.
The elements that are placed outside of the periodic table are called transactinides. These elements are usually placed in a separate row below the main table and are synthetic elements that do not occur naturally on Earth.
Non-metals are found on the right side of the periodic table.
The elements in group 3-12 are transition elements. They are placed in centre of periodic table.
The elements with similar properties are placed in groups. Periodic table contain 18 groups.
Mendeleev left blank spaces because certain elements on the Periodic Table were not known at that time. He knew that in the future, those elements would be found and placed on the periodic table.
The f-block elements are placed at the bottom of the periodic table because if they were placed where they belong the periodic table would be too big to fit on a normal sheet of paper.