SUMMARY / RELATED TOPICS

Dividing line between metals and nonmetals

The dividing line between metals and nonmetals can be found, in varying configurations, on some representations of the periodic table of the elements. Elements to the lower left of the line display increasing metallic behaviour; when presented as a regular stair-step, elements with the highest critical temperature for their groups lie just below the line. This line has been called the amphoteric line, the metal-nonmetal line, the metalloid line, the semimetal line, or the staircase, it is erroneously referred to as the Zintl border or the Zintl line. The last two terms instead refer to a vertical line sometimes drawn between groups 13 and 14; this particular line was christened by Laves in 1941. It differentiates group 13 elements from those in and to the right of group 14; the former combine with electropositive metals to make intermetallic compounds whereas the latter form salt-like compounds. References to a dividing line between metals and nonmetals appear in the literature as far back as at least 1869.

In 1891, Walker published a periodic'tabulation' with a diagonal straight line drawn between the metals and the nonmetals. In 1906, Alexander Smith published a periodic table with a zigzag line separating the nonmetals from the rest of elements, in his influential textbook Introduction to General Inorganic Chemistry. In 1923, Horace G. Deming, an American chemist, published short and medium form periodic tables; each one had a regular stepped line separating metals from nonmetals. Merck and Company prepared a handout form of Deming's 18-column table, in 1928, circulated in American schools. By the 1930s Deming's table was appearing in encyclopaedias of chemistry, it was distributed for many years by the Sargent-Welch Scientific Company. A dividing line between metals and nonmetals is sometimes replaced by two dividing lines. One line separates metalloids. Mendeleev wrote that,'It is... impossible to draw a strict line of demarcation between metals and nonmetals, there being many intermediate substances'.

Several other sources note ambiguity as to the location of the dividing line. Deming himself noted that the line could not be drawn accurately. Abraham M, Coshow, D & Fix, W 1994, Periodicity: A source book module, version 1.0. Chemsource, Inc. New York, viewed 26 Aug 11 Brown L & Holme T 2006, Chemistry for engineering students, Thomson Brooks/Cole, Belmont CA, ISBN 0-495-01718-3 De Graef M & McHenry ME 2007, Structure of materials: an introduction to crystallography and symmetry, Cambridge University Press, Cambridge, ISBN 0-521-65151-4 Deming HG 1923, General chemistry: An elementary survey, John Wiley & Sons, New York DiSalvo FJ 2000,'Challenges and opportunities in solid-state chemistry', Pure and Applied Chemistry, vol. 72, no. 10, pp. 1799–1807, doi:10.1351/pac200072101799 Emsley J, 1985'Mendeleyev's dream table', New Scientist, 7 March, pp. 32–36 Fluck E 1988,'New notations in the period table', Pure and Applied Chemistry, vol. 60, no. 3, pp. 431–436 Glinka N 1959, General chemistry, Foreign Languages Publishing House, Moscow Hawkes SJ 2001,'Semimetallicity', Journal of Chemical Education, vol.

78, no. 12, pp. 1686–87, doi:10.1021/ed078p1686 Herchenroeder JW & Gschneidner KA 1988,'Stable and nonexistent allotropes', Journal of Phase Equilibria, vol. 9, no. 1, pp. 2–12, doi:10.1007/BF02877443 Hinrichs GD 1869,'On the classification and the atomic weights of the so-called chemical elements, with particular reference to Stas's determinations', Proceedings of the American Association for the Advancement of Science, vol. 18, pp. 112–124 Horvath 1973,'Critical temperature of elements and the periodic system', Journal of Chemical Education, vol. 50, no. 5, pp. 335–336, doi:10.1021/ed050p335 Housecroft CE & Constable EC 2006, Chemistry, 3rd ed. Pearson Education, England, ISBN 0-13-127567-4 King RB 2005, Encyclopedia of inorganic chemistry, 2nd ed. John Wiley & Sons, Chichester, p. 6006, ISBN 0-470-86078-2 Kniep R 1996,'Eduard Zintl: His life and scholarly work', in SM Kauzlarich, Chemistry and bonding of Zintl phases and ions, VCH, New York, pp. xvii–xxx, ISBN 1-56081-900-6 Kotz JC, Treichel P & Weaver GC 2005, Chemistry & chemical reactivity, 6th ed. Brooks/Cole, Belmont, CA, ISBN 0-534-99766-X Levy J 2011, The bedside book of chemistry, Pier 9, Millers Point, Sydney, ISBN 978-1-74266-035-6 MacKay KM & MacKay RA 1989, Introduction to modern inorganic chemistry, 4th ed. Blackie, Glasgow, ISBN 0-216-92534-7 Mendeléeff DI 1897, The principles of chemistry, vol.

1, 5th ed. trans. G Kamensky, AJ Greenaway, Green & Co. London Miles WD & Gould RF 1976, American chemists and chemical engineers, vol. 1, American Chemical Society, Washington Nordell KJ & Miller GJ 1999,'Linking intermetallics and Zintl compounds: An investigation of ternary trielides forming the NaZn13 structure type', Inorganic Chemistry, vol. 38, no. 3, pp. 579–590 Norman NC 1997, Periodicity and the s- and p-block elements, Oxford University, Oxford, ISBN 0-19-855961-5 Roher GS 2001, Structure and bonding in crystalline materials, Cambridge University Press, Cambridge, ISBN 0-521-66379-2 Smith A 1906, Introduction to general inorganic chemistry, The Century Company, New York Swenson J 2005,'Classification of noble gases', in Ask a scientist, Chemistry archive Tarendash AS 2001, Let's review: Chemistry, the physical setting, Barron's Educational Series, New York, ISBN 0-7641-16

IEEE Alexander Graham Bell Medal

The IEEE Alexander Graham Bell Medal is an award honoring "exceptional contributions to communications and networking sciences and engineering" in the field of telecommunications. The medal is one of the highest honors awarded by the Institute of Electrical and Electronics Engineers for achievements in telecommunication sciences and engineering, it was instituted in 1976 by the directors of IEEE, commemorating the centennial of the invention of the telephone by Alexander Graham Bell. The award is presented either to a team of two or three persons; the institute's reasoning for the award was described thus: The invention of the telephone by Alexander Graham Bell in 1876 was a major event in electrotechnology. It was instrumental in stimulating the broad telecommunications industry that has improved life throughout the world; as an individual, Bell himself exemplified the contributions that scientists and engineers have made to the betterment of mankind. Recipients of the award receive a gold medal, bronze replica, an honorarium.

As listed by the IEEE: Alexander Graham Bell honors and tributes IEEE Medal of Honor IEEE awards World Communication Awards