93
Np
237
Neptunium
Actinide
Period 7
Block f
Neptunium is a chemical element of the periodic table with chemical symbol Np and atomic number 93 with an atomic weight of 237 u and is classed as actinide. Neptunium is solid at room temperature.
Neptunium in the periodic table
| Symbol | Np |
| Atomic number | 93 |
| Group | - |
| Period | 7 |
| Block | f |
| Classification | Actinide |
| Appearance | Silvery metallic |
| Color | Silver |
| Number of protons | 93 p+ |
| Number of neutrons | 144 n0 |
| Number of electrons | 93 e- |
From Wikipedia, the free encyclopediaNeptunium is a chemical element with symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.
Physical properties
| Phase at STP | Solid |
| Density | 20.45 g/cm3 |
| Atomic weight | 237 u |
Thermal properties
| Melting point | 912 K 638.85 °C 1181.93 °F |
| Boiling point | 4447 K 4173.85 °C 7544.93 °F |
| Heat of vaporization | 336 kJ/mol |
Atomic properties
| Electronegativity (Pauling Scale) | 1.36 |
| Electron affinity | 45.85 kJ/mol |
| Oxidation states | +2, +3, +4, +5, +6, +7 (an amphoteric oxide) |
| Ionization energies |
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Electron configuration for neptunium
Electron configuration Shorthand configuration | [Rn] 5f4 6d1 7s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Full configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f4 6s2 6p6 6d1 7s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Electron configuration chart |
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| Electrons per shell | 2, 8, 18, 32, 22, 9, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valency electrons | 6 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bohr model | Figure: Shell diagram of Neptunium (Np) atom. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Orbital Diagram
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The history of Neptunium
| Discovery | Edwin McMillan, Philip H. Abelson (1940) |
Discovery of neptunium Neptunium was the first transuranium element to be synthesized, produced in 1940 at Berkeley by Edwin McMillan and Philip Abelson through neutron bombardment of uranium-238. It was named after the planet Neptune, the next planet beyond Uranus, continuing the planetary naming convention. Trace amounts of neptunium also occur naturally in uranium ores. | |
| Original word | Neptunus |
| Language of origin | Latin |
| Name source | Astronomical body |
| Meaning | “Neptune (planet)” |
Naming The element is named after the planet Neptune, continuing the planetary naming sequence beyond uranium. | |