Transition metal electron configurations

Symbol Eu atomic number 63 atomic weight 151.97 a lanthanide group inner transition metal electron configuration [Xe]4/ 5di6s2 (partially filled orbitals) valence states +3 and +2. 

Symbol Ir atomic number 77 atomic weight 192.22 a Group VIII (Group 8) transition metal electron configuration [Xe]4/i45d 6s2 common valence states -1-3 and +4 valence states 0, -i-l, +2, -i-5 and -i-6 are known two natural isotopes, lr-191 (37.30%) and Ir-193 (62.70%) The element has 28 radioisotopes, ranging in masses from 170 to 198. 

Symbol Lu atomic number 71 atomic weight 174.97 a lanthanide series element an /-block inner-transition metal electron configuration [Xe]4/i45di6s2 valence -1-3 atomic radius (coordination number 12) 1.7349A ionic radius (Lu3+) 0.85A two naturally-occurring isotopes Lu-176 (97.1%) and Lu-175(2.59%) Lu-172 is radioactive with a half-life of 4xl0i° years (beta-emission) several artificial isotopes known, that have mass numbers 155, 156, 167—174, 177—180. 

Symbol Mn atomic number 25 atomic weight 54.938 a Group VIIB (Group 7) transition metal electron configuration [Ar]4s23d atomic radius 1.27A valence 0, -i-l, +2, -i-3, +A, +5, +6, +7 most common oxidation states +2, +A and +1] stable natural isotope Mn-55 (100%)... 

Symbol Pm atomic number 61 atomic weight 145 a lanthanide series inner-transition metal electron configuration [Xe]4/56s2 partially filled f orbitals valence states -i-3 ionic radius Pm " 0.98A aU isotopes of promethium are radioactive twenty-two isotopes in the mass range 134-155 longest-lived isotope Pm-145, ti/2 17.7 year shortest-bved isotope Pm-140, ti/2 9.2 sec. 

Symbol Pa atomic number 91 atomic weight 231.04 an actinide series radioactive element an inner-transition metal electron configuration [Rn]5/26di7s2 valence states +4 and +5 atomic radius 1.63A (for coordination number 12) twenty-two isotopes are known in the mass range 215-218,... 

Vanadium [7440-62-2] V, (at. no. 23, at. wt 50.942) is a member of Group 5 (VB) of the Periodic Table. It is a gray body-centered-cubic metal in the first transition series (electronic configuration When highly pure, it is very soft and dutile. Because of its high melting point, vanadium is referred to as a... 

Although transition metal alkylidene complexes, i.e., carbene complexes containing only hydrogen or carbon-based substituents, were first recognized over 15 years ago, it is only relatively recently that Ru, Os, and Ir alkylidene complexes have been characterized. Neutral and cationic complexes of these Group 8 metals are known for both metal electron configurations d8 and d6. The synthesis, structural properties, and reactivity of these compounds are discussed in this section. 

Table 4.2. Lewis-like oxidation numbers (n07L), formal d count, metal electron configuration (eep, Chp) and minimum and maximum coordination numbers (ncs) for low-spin normal-valent compounds of group 6-11 transition metals...

Symbol Dy atomic number 66 atomic weight 162.50 a lanthanide series, inner transition, rare earth metal electron configuration [Xe]4 5di6s2 atomic volume 19.032 cm /g. atom atomic radius 1.773A ionic radius 0.908A most common valence state +3. 

Symbol Tb atomic number 65 atomic weight 158.925 a lanthanide series element an inner-transition rare earth metal electron configuration fXe]4/96s2 valence states -i-3, +4 mean atomic radius 1.782A ionic radii, Tb3+... 

The next element, scandium, begins a series of ten elements (scandium through zinc) called the transition metals, whose configurations are obtained by adding electrons to the five 3d orbitals. The configuration of scandium is... 

In Section 7.10 we saw that in the first-row transition metals (Sc to Cu), the 4 orbital is always filled before the 3d orbitals. Consider manganese, whose electron configuration is [Ar]4 3d. When the Mn + ion is formed, we might expect the two electrons to be removed from the 3d orbitals to yield [Ar]4x 3rf. In fact, the electron configuration of Mn is [Ar]3d The reason is that the electron-electron and electron-nucleus interactions in a nentral atom can be quite different from those in its ion. Thus, whereas the 4 orbital is always filled before the 3d orbital in Mn, electrons are removed from the 4s orbital in forming Mn + because the 3d orbital is more stable than the 4 orbital in transition metal ions. Therefore, when a cation is formed from an atom of a transition metal, electrons are always removed first from the ns orbital and then from the (n - l)d orbitals. 

Transition metal clusters in which the metals are coordinated to each other and to 7r-acid ligands are known for all the metals of Groups VI, VII, and VIII. Clusters of the formally zero-valent Group IB metals (electron configuration will be included in this survey because of... 

You should realize that the metal ion in question is a transition metal ion because it has five electrons in the 3d subshell. Remember that in a transition metal ion, the (n l)d orbitals are more stable than the ns orbital. Hence, when a cation is formed fiom an atom of a transition metal, electrons are always removed first from the ns orbital arrd then fiom the n- )d orbitals if necessary. Since the metal ion has a +3 charge, three electrons have been removed. Since the 45 subshell is less stable than the 3d, two electrons would have been lost from the 45 and one electron fiom the 3d. Therefore, the electron configuration of the neutral atom is [Ar]45 3(/. This is the electron configirration of iron. Thus, the metal is iron. 

For certain transition metals, electronic effects in an unfilled d-shell can cause significant variation in M-L bond length and there has been some effort towards adding these structural-electronic effects to MM models. Bond order corrections have been used to modify ro to account for n back-bonding and the trans influence. Empirical relationships based on metal electron configuration have been used to obtain ro values for d , d and d metal ions. Two methods have been reported for the prediction of the magnitude and direction of the Jahn-Teller effect. ... 

Calculations on diatomic molecules of transition elements have begun. but so far are restricted to the first few elements. A ligand-field theory for these molecules " based on the anticipated transition metal ion configuration (e.g., 3d for Ti + in TiO) was not successful and the configurations including one or two electrons of the transition metal ion must be considered.Cheetham and Barrow ) ground states predicted... 

Copper differs in its chemistry from the earlier members of the first transition series. The outer electronic configuration contains a completely-filled set of d-orbitals and. as expected, copper forms compounds where it has the oxidation state -)-l. losing the outer (4s) electron and retaining all the 3d electrons. However, like the transition metals preceding it, it also shows the oxidation state +2 oxidation states other than -l-l and - -2 are unimportant. 

Not all ligands use just two electrons to bond to transition metals Chromium has the electron configuration [Ar]4s 3rf (6 valence electrons) and needs 12 more to satisfy the 18 electron rule In the compound (benzene)tricarbonylchromium 6 of these 12 are the tt elec Irons of the benzene ring the remammg 6 are from the three carbonyl ligands... 

Polyatomic molecules cover such a wide range of different types that it is not possible here to discuss the MOs and electron configurations of more than a very few. The molecules that we shall discuss are those of the general type AFI2, where A is a first-row element, formaldehyde (FI2CO), benzene and some regular octahedral transition metal complexes. 

---