Sodium
Sodium (钠, symbol Na) is chemical element number 11, an Alkali Metal in period 3, group 1 of the periodic table, with a standard atomic weight of about 22.99. Soft silvery metal, highly reactive with water. Essential for animal life.
Properties
| Atomic number | 11 |
|---|---|
| Symbol | Na |
| Atomic mass | 22.99 u |
| Category | Alkali Metal |
| Period | 3 |
| Group | 1 |
| Electron configuration | [Ne] 3s¹ |
| Electronegativity | 0.93 |
| Covalent radius | 166 pm |
| Density | 0.971 g/cm³ |
| Melting point | 370.87 K |
| Boiling point | 1156 K |
| Discovery | Humphry Davy, 1807 |
Overview
Soft silvery metal, highly reactive with water. Essential for animal life. Sodium (Na) holds position 11 in the periodic table, an Alkali Metal in period 3, group 1. As an alkali metal it is soft and highly reactive, releasing hydrogen on contact with water, and is usually stored away from air and moisture.
Its electron configuration is [Ne] 3s¹, with 1 electron in the outer shell, and an electronegativity of about 0.93 (Pauling). Around 25 °C it is usually a solid; it melts near 370.87 K (97.7 °C), boils near 1156 K (882.9 °C), has a density around 0.971 g/cm³.
In industry and daily life it turns up in Agriculture / Fertiliser and Energy / Batteries. Compounds featured on this site include NaOH, NaCl and Na₂CO₃. On the safety side, it carries a moderate hazard rating. It was first described by Humphry Davy in 1807.
Electron shells
Electrons per shell: 2 · 8 · 1
Main uses
- Agriculture / Fertiliser
- Energy / Batteries
Hazard
Compounds containing Sodium
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.