102No[259]
Nobelium (No)
Element 102 · Actinide
Nobelium (No) is a chemical element with atomic number 102. It is classified as an actinide in period 7 of the periodic table (the f-block). Its most stable known isotope has mass number 259 and its ground-state electron configuration is [Rn] 5f¹⁴ 7s².
Nobelium facts
| Atomic number (Z) | 102 |
|---|---|
| Symbol | No |
| Mass number of most stable isotope | [259] |
| Category | Actinide |
| Group | — (f-block) |
| Period | 7 |
| Block | f-block |
| Electron configuration | [Rn] 5f¹⁴ 7s² |
| Electronegativity (Pauling) | 1.3 |
| State at 20 °C | Unknown (synthetic) |
| Protons / electrons | 102 / 102 |
| Neutrons (most common isotope, approx.) | 157 |
| Molar mass | 259 g/mol |