alkali metal
alkali metal
alkali metal
n.（名词）
Any of a group of soft, white, low-density, low-melting, highly reactive metallic elements, including lithium, sodium, potassium, rubidium, cesium, and francium.
碱金属：一组硬度低、白色、低密度、低熔点、易发生反应的金属元素的任一种，包括锂、钠、钾、铷、铯和钫
