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Bài giảng Hóa học - Chương 9: Nhóm IIA

Bài giảng cung cấp cho người học các kiến thức: Nhóm IIA, tính kim loại, số oxi hóa, thế điện cực, tính chất lý học, tính chất hóa học,. Hi vọng đây sẽ là một tài liệu hữu ích dành cho các bạn sinh viên đang theo học môn dùng làm tài liệu học tập và nghiên cứu. chi tiết nội dung tài liệu. | GROUP 2: THE ALKALINE EARTH METALS Emerald is based on the mineral beryl: 3BeO·Al2O3 ·6SiO2 Principle forms: carbonates, sulfates and silicates Oxides and hydroxides only sparingly soluble. Basic or “alkaline” Compounds do not decompose on heating. Therefore named “earths” Heavier elements compounds are more reactive and are similar to Group I (also in other respects). Properties and Trends in Group 2A Group 2A shows the same general trends of increasing atomic and ionic sizes and decreasing ionization energies from top to bottom as does group 1A. The higher densities of the group 2A metals are mainly a consequence of the large differences in atomic sizes. The group 2A metals are all good reducing agents. Mg(OH)2 is virtually insoluble in water, however As the cation size increases from top to bottom on the periodic table, interionic attractions decrease in strength and the solubilities of the compounds in water increase. Ba(OH)2 is sufficiently soluble to be used as a titrant in acid–base titrations. ĐẶC ĐIỂM CHUNG Là kim loại hoạt động, tăng dần từ Be Ra. Kém so với KL kiềm do Z lớn, r nhỏ hơn Dễ mất 2e trở thành M2+ trong hợp chất và trong dung dịch Thế điện cực tương đương KL kiềm Thể hơi chỉ bao gồm phân tử 1 nguyên tử Ion không màu; nhiều hợp chất ít tan Be khác nhiều hơn so với Li và các nguyên tố trong nhóm; Be giống nhiều Al, Mg giống nhiều Zn . These were named alkaline earths because of their intermediate nature between the alkalis (oxides of the alkali metals) and the rare earths (oxides of rare earth metals). The alkaline earth metals are silvery colored, soft, low-density metals, which react readily with halogens to form ionic salts, and with water, though not as rapidly as the alkali metals, to form strongly alkaline (basic) hydroxides. For example, where sodium and potassium react with water at room temperature, magnesium reacts only with steam and calcium with hot water. Mg + 2H2O → Mg(OH)2 + H2 Beryllium is an exception: It does not react with . | GROUP 2: THE ALKALINE EARTH METALS Emerald is based on the mineral beryl: 3BeO·Al2O3 ·6SiO2 Principle forms: carbonates, sulfates and silicates Oxides and hydroxides only sparingly soluble. Basic or “alkaline” Compounds do not decompose on heating. Therefore named “earths” Heavier elements compounds are more reactive and are similar to Group I (also in other respects). Properties and Trends in Group 2A Group 2A shows the same general trends of increasing atomic and ionic sizes and decreasing ionization energies from top to bottom as does group 1A. The higher densities of the group 2A metals are mainly a consequence of the large differences in atomic sizes. The group 2A metals are all good reducing agents. Mg(OH)2 is virtually insoluble in water, however As the cation size increases from top to bottom on the periodic table, interionic attractions decrease in strength and the solubilities of the compounds in water increase. Ba(OH)2 is sufficiently soluble to be used as a titrant in .