P
Phosphorus
Element 15 · 30.974 u
Phosphorus is essential to life, forming part of DNA, RNA, and ATP.
Physical Properties
| Atomic Mass | 30.974 u |
| Density | 1.82 g/cm³ |
| Melting Point | 317.3 K |
| Boiling Point | 553.65 K |
| Appearance | Colorless/red/white waxy solid |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 2.19 (Pauling) |
| 1st Ionization Energy | 1011.8 kJ/mol |
| Electron Affinity | 72.0 kJ/mol |
| Oxidation States | -3, -2, -1, +1, +2, +3, +4, +5 |
Atomic Properties
| Electron Configuration | [Ne] 3s2 3p3 |
| Atomic Radius | 98.0 pm |
| Covalent Radius | 107.0 pm |
| Van der Waals Radius | 180.0 pm |
Discovery
| Discovered By | Hennig Brand |
| Discovery Year | 1669 |
| Location | Hamburg, Germany |
| Named After | Greek 'phosphoros' meaning light-bearing |
About Phosphorus
Phosphorus exists in several allotropes, the most common being white and red. White phosphorus is highly toxic and pyrophoric, glowing in the dark. Red phosphorus is more stable and less toxic. Phosphorus was the first element discovered by a named individual.
Uses & Applications
Fertilizers (phosphates), matches, detergents, pesticides, steel production, and food additives.
Fun Fact
Phosphorus was discovered by Hennig Brand in 1669 while boiling over 1,500 gallons of human urine looking for the philosopher's stone.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 31 | 1.0% | - | Yes |
Electron Configuration
[Ne] 3s2 3p3