碱金属被发现在元素周期表的ⅠA族，是非常活泼的金属而不在直接自然界中出现。这些金属的原子最外电子层只有1个电子。因此非常容易失去电子而与其他元素构成的离子化合物。像所有金属一样，他们具有很好的延展性并且是电和热的良导体。他们比大多数金属柔软。Cs和Fr是他们中最活泼的。碱金属接触水会爆炸德语口译。

The alkali metals, found in group 1 of the periodic table (formerly known as group IA), are very reactive metals that do not occur freely in nature. These metals have only one electron in their outer shell. Therefore, they are ready to lose that one electron in ionic bonding with other elements. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals. Cesium and francium are the most reactive elements in this group. Alkali metals can explode if they are exposed to water.

1915年,通过煤焦油引起兔发生癌症发现癌形成的试验证据.对化学物质致癌理论的认识在此前一个世纪发现烟囱清扫工中有高癌发病率现象时就开始了深圳翻译公司.
1915 Coal tar gives rabbits cancer in experimental proof of carcinogenesis. The theory that chemicals had cancer-causing potential began with observations more than a century earlier of the high rate of cancer among chimney sweeps.