99 predicted 2 · 8 · 18 · 32 · 29 · 8 · 2

Einsteinium, Es, element 99

Actinide· Period 7· f-block

Configuration [Rn]5f¹¹7s²

Atomic weight: 252Da
Phase: solid
Density: 8.84g/cm³
Melting point: 1,133.15K 860 °C
Boiling point: 1,269K, predicted 996 °C
Electronegativity: 1.3

Appearance is unknown, however it is most probably metallic and silver or gray in color. Radioactive metallic transuranic element belonging to the actinoids. Es-254 has the longest half-life of the eleven known isotopes at 270 days. First identified by Albert Ghiorso and associates in the debris of the 1952 hydrogen bomb explosion. In 1961 the first microgram quantities of Es-232 were separated. While einsteinium never exists naturally, if a sufficient amount was assembled, it would pose a radiation hazard. Description from mendeleev.

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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

4 of 5 fields have a value for einsteinium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.: 252Da; Source: mendeleev
Electron configuration: [Rn]5f¹¹7s²; Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰4f¹⁴5s²5p⁶5d¹⁰5f¹¹6s²6p⁶7s²; Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.: 2 · 8 · 18 · 32 · 29 · 8 · 2; Source: Worked outfrom electron configuration

No data uncertainty of the atomic weight.