---
title: "Sodium (Na): Atomic Mass, Electron Configuration & Properties"
url: https://www.moldraw.com/elements/sodium.html
description: "Sodium (Na), element 11: atomic mass 22.99, electron configuration [Ne] 3s¹, group 1, period 3, s-block alkali metal. Melting and boiling point, density, electronegativity and shells."
lang: en
publisher: Scidart Academy
generated: 2026-11-03
---
11Na22.99

# Sodium (Na) – element 11

Sodium is a chemical element with the symbol **Na** and atomic number **11**. It is a alkali metal in group 1 (alkali metals), period 3 of the periodic table (s-block), and is a solid at room temperature.

Sodium (Na) has atomic number 11, atomic mass 22.99 u and electron configuration [Ne] 3s1.

[Download periodic table PDF](https://www.moldraw.com/printables/periodic-table.pdf)[Open interactive periodic table](https://www.moldraw.com/tools/free-chem-tools/interactive-periodic-table.html)

## Sodium facts

| Symbol | Na |
| --- | --- |
| Atomic number | 11 |
| Atomic mass | 22.99 u (g/mol) |
| Category | alkali metal |
| Group | group 1 (alkali metals) |
| Period | 3 |
| Block | s-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s1 |
| Noble-gas notation | [Ne] 3s1 |
| Electrons per shell | 2, 8, 1 |
| Valence electrons | 1 |

## Bohr model and shells

Sodium has 11 electrons in 3 shells: 2, 8, 1. Full configuration and noble-gas notation are in the table; work out any element or ion with the [electron configuration calculator](https://www.moldraw.com/tools/free-chem-tools/electron-configuration-calculator.html).

## Physical and atomic properties

| Melting point | 370.944 K (97.8 °C) |
| --- | --- |
| Boiling point | 1156.09 K (882.9 °C) |
| Density | 0.968 g/cm³ |
| Electronegativity (Pauling) | 0.93 |
| Electron affinity | 52.867 kJ/mol |
| Ionization energies | 495.8, 4562, 6910.3 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 28.23 J/(mol·K) |
| Discovered by | Humphry Davy |

Use the atomic mass in the [molar mass calculator](https://www.moldraw.com/tools/free-chem-tools/molar-mass-calculator.html) for any formula containing Na.

## Position in the periodic table

Tap any element to open its page.

## Frequently asked questions

### What is the atomic mass of sodium?

The atomic mass of sodium is 22.99 u, so one mole of sodium atoms weighs 22.99 g.

### What is the electron configuration of sodium?

Sodium has 11 electrons: 1s² 2s² 2p⁶ 3s¹, or [Ne] 3s¹ in noble-gas notation. Electrons per shell: 2, 8, 1.

### How many valence electrons does sodium have?

Sodium has 1 valence electron (group 1).

### Is sodium a metal?

Yes. Sodium is a alkali metal.

### Where is sodium on the periodic table?

Sodium is in group 1 (alkali metals), period 3, in the s-block.

Data: [Periodic-Table-JSON](https://github.com/Bowserinator/Periodic-Table-JSON) (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.