
Veli Pekka Pyykkö (born 12 October 1941)
is a Finnish academic. He was professor of Chemistry at the
University of Helsinki
The University of Helsinki (, ; UH) is a public university in Helsinki, Finland. The university was founded in Turku in 1640 as the Royal Academy of Åbo under the Swedish Empire, and moved to Helsinki in 1828 under the sponsorship of Alexander ...
.
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
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods") and columns (" groups"). It is an icon of chemistry and is widely used in physics and other s ...
of elements,
known as the
Pyykkö model.
Pyykkö has also studied the
relativistic effects present in heavy atoms and their effects in
NMR
Nuclear magnetic resonance (NMR) is a physical phenomenon in which atomic nucleus, nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near and far field, near field) and respond by producing ...
.
Pyykkö model
After the 118 elements now known, Pekka Pyykkö predicts that the orbital shells will fill up in this order:
*8s,
*5g,
*the first two spaces of 8p,
*6f,
*7d,
*9s,
*the first two spaces of 9p,
*the rest of 8p.
He also suggests that period 8 be split into three parts:
*8a, containing 8s,
*8b, containing the first two elements of 8p,
*8c, containing 7d and the rest of 8p.
The compact version:

Pekka Pyykkö correctly predicted the existence of
chemical bond
A chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds or through the sharing of electrons a ...
s between
gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...
and the
noble gas
The noble gases (historically the inert gases, sometimes referred to as aerogens) are the members of Group (periodic table), group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some ...
xenon
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...
, which is usually inert; this bond is known to occur in the
cation
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
ic
complex
Complex commonly refers to:
* Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe
** Complex system, a system composed of many components which may interact with each ...
tetraxenonogold(II) (). He also correctly predicted the existence of gold–
carbon
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...
triple bond
A triple bond in chemistry is a chemical bond between two atoms involving six Electron pair bond, bonding electrons instead of the usual two in a covalent bond, covalent single bond. Triple bonds are stronger than the equivalent covalent bond, sin ...
s.
[Scientific American June 2013, "Cracks in the Periodic Table". p. 72.]
References
1941 births
Living people
People involved with the periodic table
Academic staff of the University of Helsinki
Finnish chemists
Schrödinger Medal recipients
Computational chemists
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