Element 36 · Krypton (Kr)
Krypton Bohr model: diagram and electrons per shell
The krypton Bohr model shows a krypton atom (Kr) as a small nucleus with its electrons circling it in 4 shells: 2 in shell K, 8 in shell L, 18 in shell M and 8 in shell N. This page has a rotating 3D krypton Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.
Rotate the krypton Bohr model in 3D
Drag to orbit, scroll to zoom.
This is a Bohr model of krypton (Kr), a simplified picture of a single krypton atom. Its nucleus holds 36 protons, and a neutral krypton atom has 36 electrons, arranged around it in 4 shells (2 in shell K, 8 in shell L, 18 in shell M and 8 in shell N).
Krypton Bohr model diagram
Krypton electrons per shell
A neutral krypton atom has 36 electrons, one for each of its 36 protons. They fill the shells from the nucleus outwards: 2 in shell K, 8 in shell L, 18 in shell M and 8 in shell N.
| Shell | Shell number (n) | Electrons | Most it can hold (2n²) | Subshells |
|---|---|---|---|---|
| K | 1 | 2 | 2 | 1s2 |
| L | 2 | 8 | 8 | 2s2 2p6 |
| M | 3 | 18 | 18 | 3s2 3p6 3d10 |
| N | 4 | 8 | 32 | 4s2 4p6 |
How the krypton Bohr model builds up, shell by shell
Watch the krypton 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, 18 in shell M and 8 in shell N) as it forms.
How to draw the krypton Bohr model
- Find the atomic number. Krypton has atomic number 36, so a neutral atom has 36 protons and 36 electrons.
- Draw the nucleus. Put a circle in the centre and write Kr in it. The 36 protons sit there with the neutrons.
- Draw the shells. Sketch 4 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, 18 in shell M and 8 in shell N.
- Check the total. 2 + 8 + 18 + 8 = 36, the atomic number, so every electron is accounted for.
Atomic data for the krypton Bohr model
The numbers behind the krypton Bohr model, grouped by topic. Radii are in picometres (pm) and energies in kilojoules per mole (kJ/mol).
Identity
- Symbol
- Kr
- Atomic number
- 36
- Atomic mass
- 83.7982 u
- Family
- Noble Gases
- Position
- group 18, period 4
- Block
- p-block
Electron configuration
- Full
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
- Shorthand
- [Ar] 3d10 4s2 4p6
- Electrons per shell
- 2, 8, 18, 8
- Outer-shell electrons
- 8 in shell N
Ionisation energies
- I₁
- 1350.8
- I₂
- 2350.4
- I₃
- 3565
- I₄
- 5070
- I₅
- 6240
- I₆
- 7570
- I₇
- 10710
- I₈
- 12138
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)
- 88
- Covalent (pm)
- 117
- Van der Waals (pm)
- 202
Electronegativity and electron affinity
- Electronegativity (Pauling)
- 3
- Electron affinity (kJ/mol)
- -96
Oxidation states
+2
Charges the element commonly takes in compounds.
Physical properties, abundance and history of krypton
Bulk properties of krypton, how common it is, who discovered it and some of its compounds.
Physical properties
- Phase at room conditions
- Gas
- Appearance
- Colorless gas, exhibiting a whitish glow in a high electric field
- Melting point
- -157.37°C (115.78 K)
- Boiling point
- -153.22°C (119.93 K)
- Density
- 0.003749 g/cm³
- Thermal conductivity (W/m·K)
- 0.009
- Specific heat (J/g·K)
- 0.248
- Heat of vaporisation (kJ/mol)
- 9.05
Abundance
- Earth's crust (mg/kg)
- 0
- Oceans (mg/L)
- 0
Discovery
- Discovered by
- William Ramsay
- Year
- 1898
Common compounds
- Krypton-81 Kr
- Krypton Kr
- Krypton-85 Kr
- Krypton-79 Kr
- Krypton-77 Kr
- Krypton, isotope of mass 87 Kr
- Krypton, isotope of mass 88 Kr
- Krypton-74 Kr
Compounds listed in the PubChem database.
Main isotopes of krypton
Isotopes of krypton share the same 36 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.
| Mass number | Natural abundance | Half-life | Decay |
|---|---|---|---|
| 78 | 0.355 % | stable | 2β⁺ |
| 80 | 2.286 % | stable | – |
| 82 | 11.593 % | stable | – |
| 83 | 11.5 % | stable | – |
| 84 | 56.987 % | stable | – |
| 86 | 17.279 % | stable | 2β⁻ |
α = alpha decay, β⁻ = beta-minus, β⁺ = beta-plus, EC = electron capture, SF = spontaneous fission, p / n = proton / neutron emission.
More about krypton
- Krypton on the periodic table – properties, isotopes, uses and the full krypton page.
- Noble Gases – all noble gas elements and their trends.
- Bohr model of every element – the Bohr model of all 118 elements.