鎝
Technetium

context: zh_tw: 在鎝發現以前，德米特里・門捷列夫就已經預測了它的許多性質。在他的週期表中，門捷列夫把這種尚未發現的元素叫做 “類錳”，符號為 Em。1937 年，鎝（準確的說是鎝 - 97）成為第一個大部分由人工製造的元素。它的英文名來自希臘語 τεχνητός，意為 “人造”。
en: Many of technetium's properties were predicted by Dmitri Mendeleev before the element was discovered. Mendeleev noted a gap in his periodic table and gave the undiscovered element the provisional name ekamanganese (Em). In 1937, technetium (specifically the technetium-97 isotope) became the first predominantly artificial element to be produced, hence its name (from the Greek τεχνητός, meaning "synthetic or artificial", + -ium).
qas: question: zh_tw: 在鎝被發現以前，是哪位科學家已經預測到它的許多特性？
en: Who was the scientist that predicted many of the properties of technetium prior to it's discovery?
answers: zh_tw: text: 德米特里・門捷列夫
en: text: Dmitri Mendeleev

context: zh_tw: 鎝是一種銀灰色放射性金屬，外觀與鉑相似。粉狀時呈灰色。純金屬鎝的晶型為六方最密堆積。在原子發射光譜中，鎝的特徵譜線位於 363.3、403.1、426.2、429.7 和 485.3 奈米。金屬鎝具有順磁性。在溫度降到 7.46 K 時，純金屬鎝的單晶成為二型超導體（type-II superconductor）。在這個溫度以下，鎝具有很高的倫敦穿透深度，在所有金屬中僅次於鈮。
en: Technetium is a silvery-gray radioactive metal with an appearance similar to platinum, commonly obtained as a gray powder.  The crystal structure of the pure metal is hexagonal close-packed. Atomic technetium has characteristic emission lines at these wavelengths of light: 363.3 nm, 403.1 nm, 426.2 nm, 429.7 nm, and 485.3 nm.The metal form is slightly paramagnetic, meaning its magnetic dipoles align with external magnetic fields, but will assume random orientations once the field is removed. Pure, metallic, single-crystal technetium becomes a type-II superconductor at temperatures below 7.46 K. Below this temperature, technetium has a very high magnetic penetration depth, greater than any other element except niobium.
qas: question: zh_tw: 鎝是什麼顏色？
en: What color is technetium?
answers: zh_tw: text: 銀灰色
en: text: silvery-gray

context: zh_tw: 在生物體內鎝沒有任何已知的功能。鎝毒性似乎比較小。連續幾個星期給小白鼠喂飼含有 15 微克 / 克鎝的食物，其血液、體重、器官重量和進食量未觀察到顯著的變化。鎝的放射毒性取決於鎝化合物組成、輻射型別和鎝同位素的半衰期。使用所有鎝同位素都必須謹慎。最大的健康風險是吸入帶有鎝同位素的灰塵，可以致肺癌。最常見的同位素鎝 - 99 釋放出低能量 β 粒子，甚至無法貫穿實驗室的玻璃器皿。因此和鎝化合物接觸時，手套箱基本沒有必要，通風櫥便可以很好的消除其危害。
en: Technetium plays no natural biological role and is not normally found in the human body. Technetium is produced in quantity by nuclear fission, and spreads more readily than many radionuclides. It appears to have low chemical toxicity. For example, no significant change in blood formula, body and organ weights, and food consumption could be detected for rats which ingested up to 15 µg of technetium-99 per gram of food for several weeks. The radiological toxicity of technetium (per unit of mass) is a function of compound, type of radiation for the isotope in question, and the isotope's half-life.All isotopes of technetium must be handled carefully. The most common isotope, technetium-99, is a weak beta emitter; such radiation is stopped by the walls of laboratory glassware.  The primary hazard when working with technetium is inhalation of dust; such radioactive contamination in the lungs can pose a significant cancer risk. For most work, careful handling in a fume hood is sufficient, and a glove box is not needed.
qas: question: zh_tw: 什麼是一種主要型別的同位素？
en: What's one of the main type of isotope?
answers: zh_tw: text: 鎝 - 99
en: text: technetium-99

question: zh_tw: 使用鎝時最危險的風險是什麼？
en: What is the most dangerous risk when working with Technetium?
answers: zh_tw: text: 吸入帶有鎝同位素的灰塵
en: text: inhalation of dust