Element 11 · Sodium (Na)
Sodium Bohr model: diagram and electrons per shell
The sodium Bohr model shows a sodium atom (Na) as a small nucleus with its electrons circling it in 3 shells: 2 in shell K, 8 in shell L and 1 in shell M. This page has a rotating 3D sodium Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.
Rotate the sodium Bohr model in 3D
Drag to orbit, scroll to zoom.
This is a Bohr model of sodium (Na), a simplified picture of a single sodium atom. Its nucleus holds 11 protons, and a neutral sodium atom has 11 electrons, arranged around it in 3 shells (2 in shell K, 8 in shell L and 1 in shell M).
Sodium Bohr model diagram
Sodium electrons per shell
A neutral sodium atom has 11 electrons, one for each of its 11 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L and 1 in shell M.
| Shell | Shell number (n) | Electrons | Most it can hold (2n²) | Subshells |
|---|---|---|---|---|
| K | 1 | 2 | 2 | 1s2 |
| L | 2 | 8 | 8 | 2s2 2p6 |
| M | 3 | 1 | 18 | 3s1 |
How the sodium Bohr model builds up, shell by shell
Watch the sodium Bohr model come together: the nucleus first, then each shell in turn, from the innermost outwards, with its electrons joining the ring. The legend names every shell and counts its electrons, so you can read off the arrangement (2 in shell K, 8 in shell L and 1 in shell M) as it forms.
How to draw the sodium Bohr model
- Find the atomic number. Sodium has atomic number 11, so a neutral atom has 11 protons and 11 electrons.
- Draw the nucleus. Put a circle in the centre and write Na in it. The 11 protons sit there with the neutrons.
- Draw the shells. Sketch 3 shells as rings around the nucleus. A shell holds at most 2n² electrons: 2 in the first, 8 in the second, 18 in the third and 32 in the fourth.
- Place the electrons. Fill from the inside out: 2 in shell K, 8 in shell L and 1 in shell M.
- Check the total. 2 + 8 + 1 = 11, the atomic number, so every electron is accounted for.
Atomic data for the sodium Bohr model
The numbers behind the sodium Bohr model, grouped by topic. Radii are in picometres (pm) and energies in kilojoules per mole (kJ/mol).
Identity
- Symbol
- Na
- Atomic number
- 11
- Atomic mass
- 22.9898 u
- Family
- Alkali Metals
- Position
- group 1, period 3
- Block
- s-block
Electron configuration
- Full
- 1s2 2s2 2p6 3s1
- Shorthand
- [Ne] 3s1
- Electrons per shell
- 2, 8, 1
- Outer-shell electrons
- 1 in shell M
Ionisation energies
- I₁
- 495.8
- I₂
- 4562
- I₃
- 6910.3
- I₄
- 9543
- I₅
- 13354
- I₆
- 16613
- I₇
- 20117
- I₈
- 25496
Energy to remove each electron in turn (kJ/mol). A sharp jump means the next electron comes from an inner shell.
Atomic radii
- Calculated (pm)
- 190
- Empirical (pm)
- 180
- Covalent (pm)
- 155
- Van der Waals (pm)
- 227
Electronegativity and electron affinity
- Electronegativity (Pauling)
- 0.93
- Electron affinity (kJ/mol)
- 52.867
Oxidation states
+1
Charges the element commonly takes in compounds.
Physical properties, abundance and history of sodium
Bulk properties of sodium, how common it is, who discovered it and some of its compounds.
Physical properties
- Phase at room conditions
- Solid
- Appearance
- Silvery white metallic
- Melting point
- 97.79°C (370.944 K)
- Boiling point
- 882.94°C (1156.09 K)
- Density
- 0.968 g/cm³
- Thermal conductivity (W/m·K)
- 142
- Specific heat (J/g·K)
- 1.228
- Molar heat capacity (J/mol·K)
- 28.23
- Heat of fusion (kJ/mol)
- 2.64
- Heat of vaporisation (kJ/mol)
- 97.9
Abundance
- Earth's crust (mg/kg)
- 23600
- Oceans (mg/L)
- 10800
Discovery
- Discovered by
- Humphry Davy
- Year
- 1807
Common compounds
- Sodium Lauryl Sulfate C12H25NaO4S
- Sodium Hypochlorite ClNaO
- Sodium Chlorate ClNaO3
- Sodium Bicarbonate CHNaO3
- Sodium Benzoate C7H5NaO2
- Sodium Butyrate C4H7NaO2
- Sodium pentachlorophenolate C6Cl5NaO
- Sodium Fluoride FNa
Compounds listed in the PubChem database.
Main isotopes of sodium
Isotopes of sodium share the same 11 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.
| Mass number | Natural abundance | Half-life | Decay |
|---|---|---|---|
| 21 | – | 22.455 s | β⁺ |
| 22 | – | 2.602 y | β⁺, e⁺, EC |
| 23 | 100 % | stable | – |
| 24 | – | 14.956 h | β⁻ |
| 25 | – | 59.1 s | β⁻ |
| 26 | – | 1071.28 ms | β⁻ |
α = alpha decay, β⁻ = beta-minus, β⁺ = beta-plus, EC = electron capture, SF = spontaneous fission, p / n = proton / neutron emission.
More about sodium
- Sodium on the periodic table – properties, isotopes, uses and the full sodium page.
- Alkali Metals – all alkali metal elements and their trends.
- Bohr model of every element – the Bohr model of all 118 elements.