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第Ⅰ卷6.[解析]:本题主要考查原子结构和分子结构的有关知识。在许多单质和化合物的分子中,原子间是通过共用电子对(即共价键)结合。要考虑分子中某个原子的最外层是否达到8电子结构,首先要知道该原子最外层原有的电子数,再加上其它原子和它形成共价键时的共用电子对数,若总和等于8则满足8电子结构,否则不满足。依次对各分子中每一个原子分析即可判断。A选项BF3分子中的B原子最外层有3个电子,每个B原子和三个F原子共用三对电子对,其最外层电子总和为:3+3=6,
Volume I 6. [Analysis]: This question focuses on the knowledge of atomic structure and molecular structure. In many simplex and compound molecules, atoms are joined by a common electron pair (ie, a covalent bond). To consider whether the outermost layer of an atom in a molecule reaches the 8-electron structure, one must first know the original electron number of the outermost layer of the atom, plus the other atom and the common electron pair when it forms a covalent bond. The sum is equal to 8 to satisfy the 8 electronic structure, otherwise it is not satisfied. Each atom in each molecule is analyzed in turn to determine. The B atom in the BF3 molecule of the A option has three electrons in the outermost layer. Each B atom and three F atoms share three pairs of electron pairs. The sum of the outermost electrons is 3+3=6.