Short answers, pulled from the story.
Swedish chemist Anders Ekeberg isolated tantalum in 1802 from mineral samples found in Sweden and Finland. He named the element after the mythological figure Tantalus because the metal refused to react when immersed in acid.
The distinction between tantalum and niobium was unequivocally demonstrated in 1864 by Christian Wilhelm Blomstrand and Henri Etienne Sainte-Claire Deville. Jean Charles Galissard de Marignac provided further confirmation in 1866 that only two elements existed.
Tantalum possesses a melting point of 3017 degrees Celsius which is exceeded among metals only by tungsten, rhenium, and osmium. It is also exceeded by carbon among all elements.
Natural tantalum consists of two stable isotopes 180mTa and 181Ta with 180mTa making up only 0.012 percent of the natural abundance. The isomeric state 180mTa is the only nuclear isomer among primordial nuclides and is the rarest of all.
Tantalum powder pressed into a pellet shape serves as one plate of a capacitor with a thin oxide layer acting as the dielectric. This construction allows for high capacitance in a small volume making it attractive for portable telephones and personal computers.