Pekka Pyykkö

Veli Pekka Pyykkö (born 12 October 1941) is a Finnish academic. He was professor of Chemistry at the University of Helsinki. From 2009–2012, he was the chairman of the International Academy of Quantum Molecular Science. He is known for his extension to the periodic table of elements, known as the Pyykkö model.

Pyykkö has also studied the relativistic effects present in heavy atoms and their effects in NMR. Provided by Wikipedia