What is the most dangerous element of the periodic table?

Answer 1

Although a reasonable and simple question, this query is difficult to answer because elements are dangerous for different reasons. Following are only some ways in which elements can be dangerous.

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ToxicityTechnically, anything is toxic (even water) if consumed in large enough quantities. Following is an incomplete list of known toxic elements. (Source: http://chemistry.about.com/od/toxicchemicals/a/toxicelements.htm). Elements marked with an asterisk (*) are both toxic and radioactive.

• Aluminum
• Americium *
• Antimony
• Arsenic
• Barium
• Beryllium
• Cadmium
• Hexavalent Chromium Cr6+
• Lead
• Mercury
• Osmium
• Polonium *
• Radium *
• Thallium
• Thorium *
• Vanadium
• Uranium *

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RadioactivityThere are also many radioactive elements, which may also be harmful, even if they are not toxic. The danger due to radioactivity depends upon both the half life of the element, as well as the decay mode. According to Rankopedia, the most dangerous radioactive elements are, in order:

• Plutonium
• Uranium
• Polonium
• Fancie
• Radon
• Neptunium
• Technetium
• Astatine
• Californium
• Einsteinium
• Radium
• Berkelium
• Bismuth
• Americium
• Thorium
• Mendelevium
• Dubnium
• Curium
• Roentgenium
• Ununquadium
• Actinium
• Ununoctium
• Seaborigium
• Protactinium

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ReactivityElements that are highly reactive are more dangerous because the interact, sometimes violently, with many common substances, including water. The resulting chemical reactions can be harmful or fatal, depending upon the circumstances. Reactivity is always between two or more elements, so there is not necessarily one single most reactive element, however the more reactive elements include:

• Fluorine
• Cesium
• Francium
• Bromine
• Potassium

Answer 2

The most dangerous element on the Periodic Table is generally considered to be radium due to its radioactive nature and high toxicity. It can pose serious health risks if ingested or inhaled, leading to radiation sickness, cancer, and other health issues. Radium was famously used in self-luminous paint for watch dials, leading to tragic health consequences for workers in the early 20th century.