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“××”牌天然水的部分特征性指標(biāo)如表所示，表中的“鈣、鎂、鉀”是指（ ）
A．分子
B．原子
C．元素
D．非金屬
【答案】分析：欲正確解答本題，須知分子、原子、元素和非金屬的概念與區(qū)別，還要了解表中的“鈣、鎂、鉀”是以什么形式存在．
解答：解：鈣、鎂、鉀都是以化合物的形式存在于水中，化合物是由元素組成的，故表中的“鈣、鎂、鉀”是指元素．故選C．
點評：本題主要考查學(xué)生對分子、原子、元素和非金屬的概念的理解，以及分辨物質(zhì)存在形式的能力．
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看下面表格，請回答問題：
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元素名稱質(zhì)量分?jǐn)?shù)元素名稱質(zhì)量分?jǐn)?shù)
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硫0.3×1013鐵0.4×108銀1.4×105
鈣0.2×1013錫1.1×107金1.5×104
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