The heaviest element known up till January 2015 has the atomic number :
The question asks for the atomic number of the heaviest element known as of January 2015.
Based on scientific knowledge up to January 2015, the heaviest element officially recognized had an atomic number of 118.
This element is Oganesson (Og).
| Atomic Number | Element Name | Status (as of Jan 2015) |
|---|---|---|
| 118 | Oganesson (Og) | Heaviest known element |
Therefore, the atomic number of the heaviest element known up till January 2015 is 118.
Whose Periodic Law was modified and adopted the Atomic number as the basis of Modern Periodic Table?