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- The division into blocks is justified by their distinctive nature: s is characterized, except in H and He, by highly electropositive metals; p by a range of very distinctive metals and non-metals, many of them essential to life; d by metals with multiple oxidation states; f by metals so similar that their separation is problematic. Useful statements about the elements can be made on the basis of the block they belong to and their position in it, for example highest oxidation state, density, melting point ... Electronegativity is rather systematically distributed across and between blocks. (en)
- Na, K, Mg and Ca are essential in biological systems. Some ... other s-block elements are used in medicine and/or occur as minor but useful contaminants in Ca bio-minerals e.g. Sr…These metals display only one stable oxidation state [+1 or +2]. This enables [their] ... ions to move around the cell without…danger of being oxidised or reduced. (en)
- Because of their complex electronic structure, the significant electron correlation effects, and the large relativistic contributions, the f-block elements are probably the most challenging group of elements for electronic structure theory. (en)
- The... elements show a horizontal similarity in their physical and chemical properties as well as the usual vertical relationship. This horizontal similarity is so marked that the chemistry of the first... series... is often discussed separately from that of the second and third series, which are more similar to one another than to the first series. (en)
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| dbp:source
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- Dolg, M., ed. (en)
- In Foundations of Chemistry, 2017 (en)
- Kneen, W. R., Rogers, M. J. W., and Simpson, P. (en)
- P. J. Stewart (en)
- Wilkins, R. G. and Wilkins, P. C. (en)
- Chemistry: Facts, patterns, and principles, Addison-Wesley, London, pp. 487−489 (en)
- The role of calcium and comparable cations in animal behaviour, RSC, Cambridge, p. 1 (en)
- Computational method in lanthanide and actinide chemistry, John Wiley & Sons, Chichester, p. xvii (en)
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