73 2 · 8 · 18 · 32 · 11 · 2

Tantalum, Ta, element 73

Transition metal· Period 6· Group 5· d-block

Configuration [Xe]4f¹⁴5d³6s²

Atomic weight: 180.948Da
Phase: solid
Density: 16.4g/cm³
Melting point: 3,290.15K 3,017 °C
Boiling point: 5,728.15K 5,455 °C
Electronegativity: 1.5

Heavy blue-grey metallic transition element. Ta-181 is a stable isotope, and Ta-180 is a radioactive isotope, with a half-life in excess of 10^7 years. Used in surgery as it is unreactive. Forms a passive oxide layer in air. Identified in 1802 by Ekeberg and isolated in 1820 by Jons J. Berzelius. Description from mendeleev.

Back to the table

The outermost shell: the valence electronsThe inner shellsThe nucleus One bead for each electron, on the ring of its shell, counted from the nucleus out. The rings turn at their own pace; the model is Bohr's picture of the atom, which places electrons in shells but not on true orbits.

Atomic properties

5 of 5 fields have a value for tantalum

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.: 180.9479Da; Source: mendeleev
Electron configuration: [Xe]4f¹⁴5d³6s²; Source: mendeleev
Uncertainty of the atomic weight: 2×10⁻⁵Da; Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰4f¹⁴5s²5p⁶5d³6s²; Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.: 2 · 8 · 18 · 32 · 11 · 2; Source: Worked outfrom electron configuration

Screening of each subshell

Clementi's screening constants: how much of the nucleus's charge the other electrons hide from an electron in each subshell. What is left is the effective nuclear charge it feels.

Subshell	Screening σ	Effective charge Z − σ
1s	1.4163	71.5837
2s	19.0702	53.9298
2p	4.4136	68.5864
3s	21.9085	51.0915
3p	21.1996	51.8004
3d	13.5589	59.4411
4s	33.2412	39.7588
4p	34.2652	38.7348
4d	36.676	36.324
4f	39.5296	33.4704
5s	50.3065	22.6935
5p	52.5265	20.4735
5d	56.632	16.368
6s	63.475	9.525