Technetium |
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Pronunciation | (tek-NEE-shee-əm) |
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Mass number | [97] |
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Technetium in the periodic cairt |
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Atomic nummer (Z) | 43 |
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Group | group 7 |
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Period | period 5 |
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Block | d-block |
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Element category | Transeetion metal |
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Electron confeeguration | [Kr] 4d5 5s2 |
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Electrons per shell | 2, 8, 18, 13, 2 |
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Pheesical properties |
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Phase at STP | solit |
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Meltin pynt | 2430 K (2157 °C, 3915 °F) |
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Bylin pynt | 4538 K (4265 °C, 7709 °F) |
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Density (near r.t.) | 11 g/cm3 |
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Heat o fusion | 33.29 kJ/mol |
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Heat o vapourisation | 585.2 kJ/mol |
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Molar heat capacity | 24.27 J/(mol·K) |
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Vapour pressur (extrapolatit)
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
2727 |
2998 |
3324 |
3726 |
4234 |
4894 |
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Atomic properties |
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Oxidation states | −3, −1, 0, +1,[1] +2, +3,[1] +4, +5, +6, +7 strangly acidic |
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Electronegativity | Pauling scale: 1.9 |
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Atomic radius | empirical: 136 pm |
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Covalent radius | 147±7 pm |
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Spectral lines o technetium |
Ither properties |
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Creestal structur | hexagonal close-packed (hcp) |
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Speed o soond thin rod | 16,200 m/s (at 20 °C) |
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Thermal conductivity | 50.6 W/(m·K) |
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Magnetic orderin | Paramagnetic |
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CAS Nummer | 7440-26-8 |
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History |
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Prediction | Dmitri Mendeleev (1871) |
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Diskivery | Carlo Perrier an Emilio Segrè (1937) |
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First isolation | Carlo Perrier an Emilio Segrè (1937) |
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Main isotopes o technetium |
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Isotope |
Abundance |
Hauf-life (t1/2) |
Decay mode |
Product |
95mTc |
syn |
61 d |
ε |
95Mo |
γ |
- |
IT |
95Tc |
96Tc |
syn |
4.3 d |
ε |
96Mo |
γ |
- |
97Tc |
syn |
2.6×106 y |
ε |
97Mo |
97mTc |
syn |
91 d |
IT |
97Tc |
98Tc |
syn |
4.2×106 y |
β− |
98Ru |
γ |
- |
99Tc |
trace |
2.111×105 y |
β− |
99Ru |
99mTc |
syn |
6.01 h |
IT |
99Tc |
γ |
- |
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| references |