| actinium | (n) a radioactive element of the actinide series; found in uranium ores, Syn. Ac, atomic number 89 |
| astatine | (n) a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium, Syn. At, atomic number 85 |
| bismuth | (n) a heavy brittle diamagnetic trivalent metallic element (resembles arsenic and antimony chemically); usually recovered as a by-product from ores of other metals, Syn. Bi, atomic number 83 |
| francium | (n) a radioactive element of the alkali-metal group discovered as a disintegration product of actinium, Syn. Fr, atomic number 87 |
| lead | (n) a soft heavy toxic malleable metallic element; bluish white when freshly cut but tarnishes readily to dull grey, Syn. atomic number 82, Pb |
| mercury | (n) a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures, Syn. atomic number 80, quicksilver, hydrargyrum, Hg |
| oxygen | (n) a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust, Syn. O, atomic number 8 |
| polonium | (n) a radioactive metallic element that is similar to tellurium and bismuth; occurs in uranium ores but can be produced by bombarding bismuth with neutrons in a nuclear reactor, Syn. Po, atomic number 84 |
| radium | (n) an intensely radioactive metallic element that occurs in minute amounts in uranium ores, Syn. Ra, atomic number 88 |
| radon | (n) a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health, Syn. Rn, atomic number 86 |
| thallium | (n) a soft grey malleable metallic element that resembles tin but discolors on exposure to air; it is highly toxic and is used in rodent and insect poisons; occurs in zinc blende and some iron ores, Syn. atomic number 81, Tl |
| 氧 | [yǎng, ㄧㄤˇ, 氧] oxygen O, atomic number 8 #4,509 [Add to Longdo] |
| 铅 | [qiān, ㄑㄧㄢ, 铅 / 鉛] lead Pb, metal, atomic number 82 #7,204 [Add to Longdo] |
| 汞 | [gǒng, ㄍㄨㄥˇ, 汞] mercury Hg, transition metal, atomic number 80 #17,266 [Add to Longdo] |
| 氡 | [dōng, ㄉㄨㄥ, 氡] radon Rn, noble gas, atomic number 86 #31,040 [Add to Longdo] |
| 镭 | [léi, ㄌㄟˊ, 镭 / 鐳] radium Ra, alkaline earth, atomic number 88 #34,678 [Add to Longdo] |
| 钋 | [pō, ㄆㄛ, 钋 / 釙] polonium Po 釙|钋, metalloid, atomic number 84 #43,144 [Add to Longdo] |
| 砹 | [ài, ㄞˋ, 砹] astatine At, radioactive halogen (or metalloid), atomic number 85 #48,371 [Add to Longdo] |
| 铊 | [tā, ㄊㄚ, 铊 / 鉈] thallium Tl, metal, atomic number 81 #48,592 [Add to Longdo] |
| 铋 | [bì, ㄅㄧˋ, 铋 / 鉍] bismuth Bi, metal, atomic number 83 #55,492 [Add to Longdo] |
| 钫 | [fāng, ㄈㄤ, 钫 / 鈁] francium Fr, unstable alkali metal 鹼性金屬|碱性金属 with atomic number 87, disintegration product of actinium 錒|锕 #56,032 [Add to Longdo] |
