The Scandium Group

Electron structure Radius (pm) Color of Origin of element name 

Pr 6s2sd°4f3 6s°5d°4f2 182 113 Green Greek praseos + didymos green twin 

Nd 6s25d°4f 6s°5d°4f3 181 112 Lilac Greek neos + didymos new twin 

Pm 6s2sd°4f5 6s°5d°4f 181 111 Pink Prometheus stole fire from heaven 

Tm 6s25d°4fi3 6s°5d°4f 176 102 Green Latin Thule northern land 

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We have not discussed in detail the transition metals of Groups Ilia, IVa, Va, or Vila. The first of these four, the scandium group, contains the rare and invariably tripositive metals, scandium (Z = 21), yttrium (Z = 39), and lanthanum (Z = 57) these elements are best considered with the rare earths and will not be taken up in this text. 

The ground state configuration of lanthanides, 4/" l5d 6s2 or 4/"6s2 does not determine the chemical behaviour of these elements. In forming Ln3+ ions, an / electron is removed. Lanthanides differ from transition elements in that 4/ orbitals are shielded and are not available for reactions. Thus lanthanides resemble more closely alkaline earths and the scandium group than transition elements in their chemistry. 

PANI Composites with Oxides of the Scandium Group of Transition Metals... 

Meanwhile, as mentioned above, the metallurgist Habashi has proposed a periodic table in which the element aluminum k moved to the top of the scandium group. Moving to chemists, Rayner Canham has published an Inorganic Chemist s Table (see figure 10.12), in which he highlights a number of unusual relationships, several of which have been reviewed in thk chapter. One particularly unusual feature of his table is the inclusion of the ions CN and NH/ because of their similarities to certain elements. 

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