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Periodic Trends: The basics. CHEMISTRY 11 May 6, 2010. The Periodic Table. The chemist Dmitri Mendeleev gave the first major attempt at organizing the elements by their physical and chemical properties Дми́трий Менделе́ев. The Periodic Law.
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Periodic Trends:The basics CHEMISTRY 11 May 6, 2010
The Periodic Table • The chemist Dmitri Mendeleev gave the first major attempt at organizing the elements by their physical and chemical properties • Дми́трий Менделе́ев
The Periodic Law • Mendeleev saw patterns in the chlorides each element made as well as the mass of each element • Each column in a periodic table contains elements with very similar properties • HEBDEN p. 160 • The properties of the chemical elements recur periodically when arranged from lowest to highest atomic number
Major Families in the Periodic Table • Alkali metals – Li, Na, K, Rb, Cs, Fr • Alkaline-Earth metals – Be, Mg, Ca, Sr, Ba, Ra • Halogens – F, Cl, Br, I, At • Chalcogens – O, S, Se, Te, Po • Noble gases – He, Ne, Ar, Kr, Xe, Rn • Transition metals – All d-block elements • Lanthanides – All 4f elements (with La) • Actinides – All 5f elements (with Ac) • Transactinides - 6d and 7p elements
Properties of Elements in Major Families • Each family contains elements which have roughly the same properties and appearance • Mendeleev used these properties to predict elements we know today • The properties are still used to predict the behaviour of the newest elements (e.g.: Transactinides Rf, Ha, Sg, Bh, Hs, Mt, Ds, Rg, Cp)
Properties of Elements in Major Families • In addition to these “chemical families”, there are three major groupings in the periodic table
Properties of Elements in Major Families NON-METALS B SEMICONDUCTORS METALS Si Ge As Se Sb Te
Metal, Non-metal, Semiconductor • Metals conduct heat and electricity very well • Metals tend to lose electrons (+ ion) • Semiconductors conduct heat and electricity somewhat • Non-metals do not conduct electricity nor heat very well • Non-metals tend to gain electrons (- ion)
Important Properties • Moving from left to right across the periodic table, elements become less metallic • Elements become more metallic moving down a family in the periodic table • Metallic elements (+ ion) react easily with non-metals (- ion) • The most metallic element is Fr; the least metallic element is F
Metallic Character INCREASING METALLIC CHARACTER
Properties of Elements in Major Families NON-METALS B SEMICONDUCTORS METALS Si Ge As Se Sb Te
Question • Look at the group 14 elements: C, Si, Ge, Sn, Pb • Which of these elements are metals, non-metals, or semiconductors? • Are there any chalcogens that are semiconductors? • Are there any halogens that are semiconductors?