Francium

Francium (/ˈfrænsiəm/ FRAN-see-əm) is a chemical element with symbol Fr and atomic number 87. It was formerly known as eka-caesium and actinium K. It is one of the two least electronegative elements, the other being caesium. Francium is a highly radioactive metal that decays into astatine, radium, and radon. As an alkali metal, it has one valence electron. Bulk francium has never been viewed. Because of the general appearance of the other element... More

Chemical Element

The 87th Element in the Periodic Table

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Radon

Radon ( /ˈreɪdɒn/ RAY-don) is a chemical element with the atomic number 86, and is represented by the symbol Rn. It is a radioactive, colorless,...

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Radium

Radium ( /ˈreɪdiəm/ RAY-dee-əm) is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline...

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Symbol:

  • Fr

Atomic mass:

  • 223 u (3.7E-16 µg )

Electronegativity (Pauling scale):

  • 0.7

Van der Waals radius:

  • 200 pm (0.00000787 )

Melting Point:

  • 26.85 °C (80.33 °F )

Boiling Point:

  • 676.85 °C (1250.3 °F )

Chemical series:

Ionization Energy:

  • 4.0727 eV (0.0000040727 MeV )

Discovery Date:

  • 1939

Discovering Country:

Electron Configuration:

  • Rn 7s1
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Namesake

Named after:

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