7th period of the periodic table now complete

[DrClaude]

http://www.iupac.org/news/news-detail/article/discovery-and-assignment-of-elements-with-atomic-numbers-113-115-117-and-118.html

 

[blue_leaf77]

Can't wait to hear how they will name these newly confirmed elements.

 

[Martin0001]

Sadly, only element 114 may have isotopes stable enough to find its way to some (quite secure) cupboard and end up to be the most expensive form of matter.

 

[newjerseyrunner]

I find it interesting that all the data I've read so far is that 118 is expected to be a slightly reactive solid, not a nobel gas.

 

[Martin0001]

I find it interesting that all the data I've read so far is that 118 is expected to be a slightly reactive solid, not a nobel gas.

Radon has atomic number 86.
You need to add 32 protons (2+6+10+14) to get next noble gas.
Hence 118 should be a noble gas.
It might not be a gas but elements of valent shell configuration s2p6 like element 118 or neon and also helium (s2) are called "noble gases".

 

[TeethWhitener]

Radon has atomic number 86.
You need to add 32 protons (2+6+10+14) to get next noble gas.
Hence 118 should be a noble gas.
It might not be a gas but elements of valent shell configuration s2p6 like element 118 or neon and also helium (s2) are called "noble gases".

I think @newjerseyrunner is referring to the prediction of a large spin-orbit coupling in Uuo, leading to a significantly enhanced reactivity. Here's an example calculation from 2005: http://pubs.acs.org/doi/abs/10.1021/jp050736o

 

[Ygggdrasil]

Radon has atomic number 86.
You need to add 32 protons (2+6+10+14) to get next noble gas.
Hence 118 should be a noble gas.
It might not be a gas but elements of valent shell configuration s2p6 like element 118 or neon and also helium (s2) are called "noble gases".

I guess it depends on how you define noble gas. If you define any group 18 element as a noble gas, then Uuo is tautologically a noble gas. However, if you think a noble gas must be both noble (i.e. unreactive, inert) and a gas at most temperatures and pressures, then perhaps Uuo may not be a noble gas. This perhaps suggests referring to group 18 as noble gases is a misnomer.

 

[newjerseyrunner]

I think @newjerseyrunner is referring to the prediction of a large spin-orbit coupling in Uuo, leading to a significantly enhanced reactivity. Here's an example calculation from 2005: http://pubs.acs.org/doi/abs/10.1021/jp050736o

Yeah, from my limited understanding, small atoms are governed entirely by the laws of quantum physics, but the much larger atoms' outer shells start having relativistic effects which change how they behave and react.

 

[Stephanus]

Can't help reading the upper left corner of the link: IUPAC: International Union of Pure and Applied Chemistry.
It does not sounds like chemistry, much less pure chemistry. It belongs to nuclear physics.

 

[blue_leaf77]

Can't help reading the upper left corner of the link: IUPAC: International Union of Pure and Applied Chemistry.
It does not sounds like chemistry, much less pure chemistry. It belongs to nuclear physics.

Is nuclear physics not an application of chemistry?
Anyway, don't sweat upon such matter of field classification. In our current age, the fields of science are interconnected they have no solid boundaries. Biophysics and physical chemistry are only some which I can recognize. IUPAC themself has been long the body responsible for standardization of atomic weights and nomenclature of inorganic and organic chemistry, among other tasks.

 

[DrClaude]

Can't help reading the upper left corner of the link: IUPAC: International Union of Pure and Applied Chemistry.
It does not sounds like chemistry, much less pure chemistry. It belongs to nuclear physics.

Historically, new elements were discovered mostly by chemical means, so its the IUPAC that got the task of naming new elements. The fact that new elements are now created in particle accelerators does not necessarily warrant that IUPAC should not be responsible for the periodic table anymore.

Ans as blue_leaf77 said, don't sweat it. There are already enough turf wars in science.

 

[TeethWhitener]

Yeah, from my limited understanding, small atoms are governed entirely by the laws of quantum physics, but the much larger atoms' outer shells start having relativistic effects which change how they behave and react.

It's relativistic in the sense that spin is a relativistic property. However, if you just accept that spin is a property of the electrons, you can get the enhanced reactivity from ordinary non-relativistic QM. It all comes down to spin-orbit coupling. For light atoms, the coupling between the orbital (and spin) angular momenta of different electrons is much larger than the coupling between an individual electron's orbital and spin angular momentum. This means that overall orbital and spin angular momenta are good quantum numbers (this is reflected in elementary atomic physics by the existence of well-defined s, p, d, f, etc. orbitals). However, the spin orbit coupling increases more quickly than the electron-electron coupling as atomic number increases. So for higher Z atoms, the spin-orbit coupling mixes these quantum numbers such that J (the overall angular momentum) is the only good quantum number. Thus, for high Z, things like "s orbital" cease to be well-defined concepts. One of the consequences of this is that periodic trends start to get less reliable for heavier elements.

 

[TeethWhitener]

Can't help reading the upper left corner of the link: IUPAC: International Union of Pure and Applied Chemistry.
It does not sounds like chemistry, much less pure chemistry. It belongs to nuclear physics.

Incidentally, if we consider protons and neutrons instead of electrons, this crossover between interparticle coupling (so-called L-S coupling) and intraparticle coupling (so called jj-coupling) happens way earlier for particles in the nucleus, so that spin-orbit coupling has to be considered at the outset to give an accurate model of the nucleus. The simplest model that does this is called the nuclear shell model, and it's pretty successful. So chemistry and physics have a lot to say to each other, even at the nuclear level.