Símbolo | Ta |
Número atómico | 73 |
Grupo | 5 (Familia del vanadio) |
Período | 6 |
Bloque | d |
Clasificación | Metal de transición |
Apariencia | Gray blue |
Color | Gris |
Número de protones | 73 p+ |
Número de neutrones | 108 n0 |
Número de electrones | 73 e- |
Fase en STP | Sólido |
Densidad | 16.69 g/cm3 |
Peso atómico | 180.948 u |
Punto de fusión | 3290 K 3016.85 °C 5462.33 °F |
Punto de ebullición | 5731 K 5457.85 °C 9856.13 °F |
Entalpía de vaporización | 737 kJ/mol |
Electronegatividad (Escala de Pauling) | 1.5 |
Afinidad electrónica | 31 kJ/mol |
Estado de oxidación | −3, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide) |
Energía de ionización |
|
Descubrimiento | Anders Gustaf Ekeberg (1802) |
Recognized as a distinct element by | Heinrich Rose (1844) |
Descubrimiento de tántalo Tantalum was discovered in Sweden in 1802 by Anders Ekeberg, in two mineral samples – one from Sweden and the other from Finland. One year earlier, Charles Hatchett had discovered columbium (now niobium), and in 1809 the English chemist William Hyde Wollaston compared its oxide, columbite with a density of 5.918 g/cm3, to that of tantalum, tantalite with a density of 7.935 g/cm3. He concluded that the two oxides, despite their difference in measured density, were identical and kept the name tantalum. After Friedrich Wöhler confirmed these results, it was thought that columbium and tantalum were the same element. This conclusion was disputed in 1846 by the German chemist Heinrich Rose, who argued that there were two additional elements in the tantalite sample, and he named them after the children of Tantalus: niobium (from Niobe, the goddess of tears), and pelopium (from Pelops). The supposed element "pelopium" was later identified as a mixture of tantalum and niobium, and it was found that the niobium was identical to the columbium already discovered in 1801 by Hatchett. |