Transition metal cations electronic configurations

Give the electron configuration and/or orbital diagram of a transition metal cation. 

Second, metal atoms carry some positive charge in the majority of their compounds. Transition metal cations have pure d configurations, in contrast to the mixed d-s configurations of free neutral transition metal atoms. There is the chemical rule that "s electrons fall down into the d level... 

C20-0035. Write valence electron configurations for the following transition metal cations (a) (b)... 

In many cases the relationships have not been so easily interpreted. For many salts, having transition metal cations, no unequivocal trend can be found (138). The electronic configuration of the cation has also been found to have an effect in this direction. However, the exact opposite trend has been reported for other compounds such as vateritetype lanthanide borates, the vibrational frequencies increase with increasing effective nuclear charge of the cation (186, 187). All this goes to indicate how comphcated this problem is. 

For transition metal cations, the valence s orbital is vacant, and all the valence electrons occupy the d orbitals. Iron, for example, which forms 2+ and 3+ cations, has the following valence electron configurations ... 

There are no anomalous elec-/ V I tron configurations for common transition metal cations. The ns orbital is vacant, and the remaining valence electrons occupy (n - 1 )d orbitals, where n is the period. 

As discussed in Sec. 1.28.3.1, the number of Ph3PAu(0) groups in the hetero-nuclear clusters of the type [M(CO)x(AuPPh3), ] is determined by the electronic demand of the transition metal M, that requires a stable 18 electron configuration. The cluster cation [Pt(dppe)(AuPPh3)4] + is an exception to this rule, since the central Pt atom only achieves 16 electrons by adding to the 10 d electrons of the Pt(0) atom the four electrons of the two Pt P bonds, and the two electrons of the... 

It may seem odd that the 4s electrons are removed before the 3d electrons in forming transition-metal cations. After all, in writing electron configurations the... 

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