Discovered By: Carlo Perrier, Emilio Segre
Discovery year: 1937
| Atomic number | 43 |
| Group | 7 |
| Period | 5 |
| Block | d |
| Electrons | 43 |
| Protons | 43 |
| Neutrons | 55 |
| Atomic weight | (98) |
| Oxidatio states | -1, +4, +7 |
| Ionic charge | Tc^7+ |
| Electron per shell | K2 L8 M18 N13 O2 |
| Electron configuration | 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^5 |
| Atomic radius | 183 pm |
| Covalent radius | 147 pm |
| Boiling point | 4265°C |
| Melting point | 2157°C |
| Phase | Solid |
| Fusion heat | 23 kJ.mol^-1 |
| Vaporization heat | 550 kJ.mol^-1 |
| Specific heat | 63 J.kg^-1K^-1 |
| Color | Silver |
| Density | 11500 kg.m^-3 |
| Molar volume | 8.5*10 ^-6 m^3.mol^-1 |
| Electic type | Conductor |
| Magnetic type | Paramagnetic |
| Volume magnetic susceptibility | 3.933*10^-4 |
| Mass magnetic susceptibility | 3.42*10^-8 m^3.kg^-1 |
| Molar magnetic susceptibility | 3.352*10^-9 m^3.mol^-1 |
| Resistivity | 2.10^-7 Ohm.m |
| Superconducting point | 7.8 K |
| Electronegativity | 1.9 |
| Valence | 7 |
| Electron affinity | 53 kJ.mol^-1 |
| First ionization energy | 702 kJ.mol^-1 |
| Radioactive | Yes |
| Half life | 6.7*10^12 s |
| Lifetime | 1.9*10^14 s |
| neutro cross section | 22 barn |
| Decay mode | Beta decay(β) |
| Thermal conductivity | 51 W.m^-1.K^-1 |

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