Методическая разработка по английскому языку для студентов факультета химии и химической технологии " Simple Chemistry" Алматы 2017
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мет. разработка по химии
| The Carbon Family
Group 14 (IVA) consists of carbon, silicon, germanium, tin, and lead. Carbon is a non-metal, silicon and germanium are metalloids, and tin and lead are metals. With 4 electrons in the valence shell, elements of the carbon family tend to form covalent compounds. With increasing mass and atomic radius these elements become increasingly metallic and have lower melting and boiling points. Group 14 elements form gaseous hydrogen compounds with difficulty. These are either unstable or combustible. Lead forms oxides, sulfides, and halides in the +4 oxidation state. The +4 oxidation state predominates in carbon, silicon, and germanium; the +2 and +4 oxidation states appear in tin, and the +2 oxidation state prevails in lead. Carbon compounds are covalent. Carbon forms double and even triple bonds with itself or other elements. It forms compounds that the heavy elements of this group do not form for example acetylene (C2H2). Silicon and the heavier elements of this group form only single bonds. Thus carbon dioxide CO2 is a gas at normal temperatures because the double bonds between carbon and oxygen create single molecules, but silicon dioxide SiO2 forms a hard rock which is quartz because it is a covalent network solid. Each silicon atom bonds to four different oxygen atoms with single bonds, and each oxygen atom bonds with two silicon atoms. Vocabulary carbon углерод silicon кремний germanium германий tin олово lead свинец valence shell валентная оболочка to form образовывать with increasing с увеличением hydrogen compounds водородные соединения to form something with difficulty образовывать что-то с трудностью unstable не устойчивый combustible возгораемый either .. or либо … либо sulfides сульфиды halides галиды oxidation state степень окисления to prevail преобладать to appear присутствовать, появляться double bonds двойные связи triple bonds тройные связи heavy тяжелый acetylene ацетилен single bonds одинарные связи thus таким образом a hard rock твердая порода between между covalent network solid ковалентное тесло с сетчатой структурой each каждый to bond to присоединяться жүктеу/скачать 422,31 Kb. Достарыңызбен бөлісу:
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