## Thallium |

Symbol | Tl |
---|---|

Latin name | Thallium |

Atomic number | 81 |

Period | 6 |

Element category | Metals |

Relative atomic mass | 204.3833 |

Group | III.A |

Electronegativity | 1.8 |

Oxidation numbers | 1, 3 |

Electron configuration | 1s ^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 3d^{10} 4s^{2} 4p^{6} 4d^{10} 5s^{2} 5p^{6} 4f^{14} 5d^{10} 6s^{2} 6p^{1} |

Density [g/cm^{3}] | 11.85 |

State | Solid |

Melting point [°C] | 303.5 |

Boiling point [°C] | 1457 |

Thermal conductivity [W m^{-1}K^{-1}] | 46.1 |

Heat capacity [J K^{-1}g^{-1}] | 0.129 |

Discovery | 1861 |

Hardness [Mohs scale] | 1.2 |

Young's modulus [GPa] | 8 |

Electrical conductivity [S m^{-1}] | 5.6 · 10 ^{6} |

Shear modulus [GPa] | 2.8 |

1.st ionization energy [eV] | 6.1083 |

2.nd ionization energy [eV] | 20.428 |

3.rd ionization energy [eV] | 29.829 |

Stable isotopes | 2 |

Unstable isotopes | 26 |