Scandium atom

In fact this explanation for the configuration of the scandium atom and most other first transition elements is inconsistent. If the 3d... 

Fig.6. Same as fig.4 for 3d type orbitals (1=2, one radial node) of the Scandium atom.

Suppose we want to write the electron configuration of scandium (atomic number 21). We can rewrite the first 12 electrons that we wrote above for magnesium, and then just keep going. As we added electrons, we filled the first shell of electrons first, then the second shell. When we are filling the third shell, we have to ask if the electrons with n = 3 and / = 2 will enter before the n = 4 and 1 = 0 electrons. Since (n + /) for the former is 5 and that for the latter is 4, we must add the two electrons with n = 4 and / = 0 before the last 10 electrons with n = 3 and / = 2. In this discussion, the values of m and s tell us how many electrons can have the same set of n and / values, but do not matter as to which come first. 

Thus, scandium, atomic number 21, has two electrons in its Is subshell, two electrons in its 2s subshell, six electrons in its 2p subshell, two electrons in its 3s subshell, six electrons in its 3p subshell, two electrons in its 4s subshell, and its last electron in the 3d subshell. 

By the MEM charge density studies, the different features of encapsulated metal atoms in C82 were revealed for La C82 [2] and Sc C82 [3]. To compare the three-dimensional shape of the metal-atom charge distribution, a section of the equi-density surface of a La C82 molecule is presented in Fig. 9 together with the result for Sc C82 (Isomer I). The equi-density level is 1.8 e/A3. The number of electrons belonging to the Sc atom of Sc C82 was 18.8(2) e, which is close to the 19.0 e of a divalent state of the scandium atom, Sc2+. This indicates that the Sc C82 (I) is an endohedral metallofullerene whose formal electronic structure is Sc2+C82. This result has brought the long discussion as to whether the Sc atom is in a divalent or trivalent state inside the carbon cage [26-29] to an end experimentally. 

Even at the Rietveld analysis level, it is concluded that the X-ray diffraction data obviously cannot be explained by the Sc2 C66 structure model based on 4059 isomer. In Sc3 C82 [7] and Sc2 C66 [6] each scandium atom donates one electron to the fullerene cage, whereas two electrons are transferred from each Sc atom to the fullerene cages in Sc C82 [3] and Sc2 C84 [4]. 

It seems that there is always one electron transfer from Sc to the fullerene cage (e.g., Sc3 C82 and Sc2 C66) when the encapsulated scandium atoms form a cluster. The published theoretical calculation [46] could not explain both the structure and the electron transfer of Sc3 C82. 

An ordered cation-deficient derivative of the NaCl structure was found in the orthorhombic SC2S3 type (168). The unit cell contains twelve rocksalt units (a = 2 ao, b = ]/2 ao, c = 3J/2 o) The cation vacancies are three-dimensionally distributed without pronounced directional preference. In each sulfur-centered octahedron two scandium atoms are missing. SC2S3, ScaSe3, Y2S3 and Y2Se3 (213) Eire normal valence compounds with non-metallic properties. 

Figures 4 and 5 Illustrate the chemistry of iron and scandium atoms reacting with water. As noted earlier, both Fe and Fe2 water adducts are formed and labeled "a" and "b", respectively, in Figure A. It is interesting that Fe2...0H2 can be photolyzed without photolyzing the Fe...OH2 adduct. The "d" peaks which result from photolysis of Fe2...0H2 indicate that a species with terminally bonded H and OH groups is formed. The photolysis of Fe2...0H2 would appear to lead to formation of the HFeFeOH species.

The scandium atoms are thought to be encapsulated as the triply charged, equilateral triangle cluster Sc3 +. 

What is the complete electron confignration of a scandium atom ... 

The triscandium endohedral fullerene Sc3 C82 has been isolated and studied by ESR.96 Synchrotron X-ray studies indicate that the three scandium atoms form a triangle and this trimer has a formal charge of three allowing formulation of the compound as (Sc3)3+C323-.113 The temperature-dependent metal cluster position inside the C82 cage has been studied.114... 

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