| Chinese | English |
| 第一族元素 | element of group Any of the monovalent metals lithium, sodium, potassium, rubidium, caesium, and francium, belonging to group 1A of the periodic table. They are all very reactive and electropositive; alkaline (任何单价金属，如：锂、钠、钾、铷、铯，属于周期表的1A族，反应性高，带正电。) |
| 第一演替阶段 | first stage of succession |
| 第七族元素 | element of group Any of the elements of the halogen family, consisting of fluorine, chlorine, bromine, iodine, and astatine (卤族元素，包含氟、氯、溴、碘、砹。) |
| 第三产业部门 | tertiary sector The part of a country or region's economy that produces services or assets lacking a tangible and storable form (一个国家或地区经济的一部分，生产服务或资产缺乏有形的和可存储的形式。) |
| 第三保护机制 | third protective mechanism |
| 第三族元素 | element of group Group III consists of two subgroups: group IIIb and group IIIa. Group IIIa consists of scandium, yttrium, and lanthanium, which is generally considered with the lanthanoids, and actinium, which is classified with the actinoids. Group IIIb, the main group, comprises boron, aluminium, gallium, indium, and thallium (第三族元素，包含两个子族：3b和3a族。3a族包含通常被归为镧系的钪、钇、镧和是属于辐射性元素的锕。3b族包含硼、铝、镓、铟、铊。) |
| 第二族元素 | element of group Any of the divalent electropositive metals beryllium, magnesium, calcium, strontium, barium, and radium, belonging to group 2A of the periodic table; alkaline earth metals (任何带正二价电荷的金属，如：铍、镁、钙、锶、钡、镭属于周期表的第2A族。) |
| 第五族元素 | element of group Group V consists of two subgroups: group Vb, the main group, and group Va. Group Va consists of vanadium, niobium, and tantalum, which are generally considered with the transition elements. The main group consists of nitrogen, phosphorus, arsenic, antimony, and bismuth (第五族元素，包含两个子族：主族56及5a族。5a族包含钒、铌和钽，通常被归为过渡金属元素。主族5b包含氮、磷、砷、锑和铋。) |
| 第六族元素 | element of group Group VI consists of two subgroups: group VIb, the main group, and group VIa. Group VIa consists of chromium, molybdenum, and tungsten. The main group consists of oxygen, sulphur, selenium, tellurium, and polonium (第六族元素包含两个子族：主族6b及6a族。6a族包含铬、钼、和钨。主族6b族包含氧、硫、硒、碲、和钋。) |
| 第四族元素 | element of group Group IV consists of two subgroups: group IVb, main group, and group IVa. Group IVa consists of titanium, zirconium, and hafnium which are generally classified as transition metals. The main group consists of carbonium, silicium, germanium, tin, and lead. The main valency of the elements is IV, and the members of the group show a variation from nonmetallic to metallic behaviour in moving down the group. The reactivity of the elements increases down the group from carbon to lead. All react with oxygen on heating (第四族元素，包含两个子族：主族4b及4a族。4a族包含通常被归为过渡金属元素的钛、锆和铪。4b族包含碳、硅、锗、锡、和铅。主要的价数是4价。此族排列从上方的非金属元素至下方的金属元素。元素的反应性由碳至铅递增，且所有元素皆可与氧在加热状况下反应。) |
