Neptunium electron configuration

Neptunium (Np), 1 463-491, 464t electronic configuration, i 474t ion type and color, l 477t metal properties of, l 482t Neral, 24 530... 

Nobelium is a member of the actinide series of elements. The ground state electron configuration is assumed to be (Rn)5fl47s2, by analogy with the equivalent lanthanide element ytterbium ([Kr]4fl46s2) there has never been enough nobelium made to experimentally verify the electronic configuration. Unlike the other actinide elements and the lanthanide elements, nobelium is most stable in solution as the dipositive cation No ". Consequently its chemistry resembles that of the much less chemically stable dipositive lanthanide cations or the common chemistry of the alkaline earth elements. When oxidized to No, nobelium follows the well-estabhshed chemistry of the stable, tripositive rare earth elements and of the other tripositive actinide elements (e.g., americium and curium), see also Actinium Berkelium Einsteinium Fermium Lawrencium Mendele-vium Neptunium Plutonium Protactinium Ruthereordium Thorium Uranium. 

The following elements also have the same electronic configuration as actinium (i.e. 5s 5pl) in their outer-most electronic orbitals, while the inner 4d orbitals are being filled, on going from element to element. Neptunium, Plutonium, Americium, Curium, Berkelium... 

In the lighter aetinides, uranium, neptunium and plutonium compounds are more thoroughly investigated. Tetravalent Pa eompoimds, probably in the form of Pa02, could become intermediate valent the electronic configuration would then be the same as in Pr02, with one or a fraction of one f electron. 

The chemical isomer shifts decrease considerably as the formal oxidation state of the neptunium increases from +3 to +6. Comparison of the shifts with electron charge densities at the nucleus derived from non-relativistic Hartree-Fock wavefunctions for 5/ to 5/ configurations showed a linear interrelationship. An approximate value for d<7 >/ of —3-5 X lO" was derived. 

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