Are There Any Undiscovered Elements?

Is the Periodic Table Complete... or Not?

Mendeleev's original periodic table contained holes.
Mendeleev's original periodic table contained holes, so he suspected there were undiscovered elements.

Question: Are There Any Undiscovered Elements?

Elements are the basic identifiable form of matter. Have you ever wondered if there are any undiscovered elements or how scientists find new elements? Here's the answer.

Answer: The answer to the question is yes and no! Although there are elements we have not yet created or found in nature, we already know what they will be and can predict their properties.

For example, element 125 has not been observed, but when it is, it will appear in a new row of the periodic table as a transition metal. Its location and properties can be predicted because the periodic table organizes elements according to increasing atomic number. Thus, there are no true 'holes' in the periodic table.

Contrast this with Mendeleev's original periodic table, which organized elements according to increasing atomic weight. At that time, the structure of the atom was not as well-understood and there were true holes in the table since elements weren't defined as clearly as they are now.

When elements of higher atomic number (more protons) are observed, it's often not the element itself that is seen, but a decay product, since these superheavy elements tend to be highly unstable. In that respect, even new elements aren't always 'discovered' directly. In some cases, insufficient amounts of the elements have been synthesized for us to know what the element looks like!

Yet, the elements are considered to be known, are named, and are listed on the periodic table. So, there will be new elements added to the periodic table, but where they will be placed on the table is already known. There won't be any new elements between, for example, hydrogen and helium or seaborgium and bohrium.

Learn More

Timeline of Element Discovery
How New Elements Are Discovered
How New Elements Are Named