99
Es
252
Einsteinium
Actinide
Period 7
Block f
Einsteinium is a chemical element of the periodic table with chemical symbol Es and atomic number 99 with an atomic weight of 252 u and is classed as actinide. Einsteinium is solid at room temperature.
Einsteinium in the periodic table
| Symbol | Es |
| Atomic number | 99 |
| Group | - |
| Period | 7 |
| Block | f |
| Classification | Actinide |
| Appearance | Silver-colored |
| Color | - |
| Number of protons | 99 p+ |
| Number of neutrons | 153 n0 |
| Number of electrons | 99 e- |
From Wikipedia, the free encyclopediaEinsteinium is a synthetic element with symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide. Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein.
Physical properties
| Phase at STP | Solid |
| Density | 8.84 g/cm3 |
| Atomic weight | 252 u |
Thermal properties
| Melting point | 1133 K 859.85 °C 1579.73 °F |
| Boiling point | 1269 K 995.85 °C 1824.53 °F |
| Heat of vaporization | - |
Atomic properties
| Electronegativity (Pauling Scale) | 1.3 |
| Electron affinity | -28.6 kJ/mol |
| Oxidation states | +2, +3, +4 () |
| Ionization energies |
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Electron configuration for einsteinium
Electron configuration Shorthand configuration | [Rn] 5f11 7s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Full configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f11 6s2 6p6 7s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Electron configuration chart |
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| Electrons per shell | 2, 8, 18, 32, 29, 8, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valency electrons | 3 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bohr model | Figure: Shell diagram of Einsteinium (Es) atom. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Orbital Diagram
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The history of Einsteinium
| Discovery | Lawrence Berkeley National Laboratory (1952) |
Discovery of einsteinium Einsteinium was discovered in the fallout from the Ivy Mike thermonuclear test in November 1952. The element formed when uranium-238 nuclei absorbed multiple neutrons in the blast. Identified by Albert Ghiorso and collaborators at Berkeley, the discovery was kept classified until 1955. It was named in honour of Albert Einstein, who had died earlier that year. | |
| Original word | Einstein |
| Language of origin | English |
| Name source | Person |
| Meaning | “Albert Einstein” |
Naming The element is named in honour of Albert Einstein, the German-born theoretical physicist who died the year before the discovery was declassified. | |