Nihonium (Nh) — element 113post-transition metal · group 13, period 7
Nihonium is a chemical element with the symbol Nh and atomic number 113. It is a post-transition metal in group 13, period 7 of the periodic table (the p-block), with a standard atomic mass of [286] u. At room temperature (25 °C) nihonium is predicted to be a solid.
# Nihonium properties
| Symbol | Nh |
|---|---|
| Atomic number | 113 |
| Atomic mass | [286] u |
| Category | post-transition metal |
| Group | 13 |
| Period | 7 |
| Block | p-block |
| Electron configuration | [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d¹⁰ 7s² 7p¹ |
| Electrons per shell | 2, 8, 18, 32, 32, 18, 3 |
| Protons / electrons | 113 / 113 |
| State at 25 °C | predicted solid |
| Melting point | 700 K (426.9 °C, 800.3 °F) (predicted) |
| Boiling point | 1400 K (1126.8 °C, 2060.3 °F) (predicted) |
| Density | 16 g/cm³ (predicted) |
| Electronegativity (Pauling) | — |
| First ionization energy | — |
| Atomic radius | — |
| Discovered | 2003 |
Values for superheavy elements are theoretical predictions; none have been measured in bulk.
# Electron configuration of nihonium
The electron configuration of nihonium is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d¹⁰ 7s² 7p¹. Its 113 electrons fill 7 shells as 2, 8, 18, 32, 32, 18, 3, so the outermost shell holds 3 electrons. As a group 13 element, nihonium has 3 valence electrons. Because only a few atoms have ever been made, this configuration is a theoretical prediction.