Quick Scoop

The heaviest known element is **oganesson**. It has atomic number **118** and is the heaviest element currently on the periodic table.

What that means

If you mean **heaviest by atomic number or overall atomic mass among known elements** , oganesson is the answer. It is a synthetic, highly radioactive element, and only a few atoms have ever been created.

Natural vs known

If you mean **heaviest naturally occurring element on Earth** , that is **uranium**. Heavier elements do exist, but they are synthetic and usually extremely short-lived.

Short version

  • Heaviest known element: oganesson.
  • Heaviest naturally occurring element: uranium.

If you want, I can also give you the heaviest element by atomic mass , by density , or by natural occurrence.