Sodium (Na)
Sodium is element 11, a alkali metal in period 3, group 1 of the periodic table. At room temperature it is a solid.
Electron configuration [Ne] 3s1
Electrons per shell 2, 8, 1
Sodium data
| Atomic number | 11 |
|---|---|
| Symbol | Na |
| Atomic mass | 22.99 u |
| Category | Alkali metal |
| Group | 1 |
| Period | 3 |
| Block | s |
| State at 25 °C | solid |
| Melting point | 371 K (97.9 °C) |
| Boiling point | 1156 K (882.9 °C) |
| Density | 0.968 g/cm³ |
| Electronegativity (Pauling) | 0.93 |
| Atomic radius | 154 pm |
| 1st ionization energy | 496 kJ/mol |
| Electron affinity | -53 kJ/mol |
| Oxidation states | -1, +1 |
| Common ion charge | + |
| Discovered | 1807 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through sodium’s configuration and its ions →
Where sodium sits
Sodium belongs to the alkali metals. Its Pauling electronegativity of 0.93 is among the lowest on the table, so it gives up electrons readily; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Sodium FAQ
What is the electron configuration of sodium?
Sodium (Z = 11) has the configuration 1s2 2s2 2p6 3s1. In noble-gas shorthand that is [Ne] 3s1.
How many valence electrons does sodium have?
1 (outer shell (n = 3)).
What is the atomic mass of sodium?
The standard atomic weight of sodium is 22.99 u, so one mole weighs 22.99 g.
Is sodium a metal?
Yes. Sodium is a alkali metal.
What is the charge of a sodium ion?
Sodium most commonly forms Na+.