Krypton (Kr) – element 36
Krypton is a chemical element with the symbol Kr and atomic number 36. It is a noble gas in group 18 (noble gases), period 4 of the periodic table (p-block), and is a gas at room temperature.
Krypton (Kr) has atomic number 36, atomic mass 83.798 u and electron configuration [Ar] 3d10 4s2 4p6.
Krypton facts
| Symbol | Kr |
|---|---|
| Atomic number | 36 |
| Atomic mass | 83.798 u (g/mol) |
| Category | noble gas |
| Group | group 18 (noble gases) |
| Period | 4 |
| Block | p-block |
| Phase at 20 °C | Gas |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 |
| Noble-gas notation | [Ar] 3d10 4s2 4p6 |
| Electrons per shell | 2, 8, 18, 8 |
| Valence electrons | 8 |
Bohr model and shells
Krypton has 36 electrons in 4 shells: 2, 8, 18, 8. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 115.78 K (-157.4 °C) |
|---|---|
| Boiling point | 119.93 K (-153.2 °C) |
| Density | 3.749 g/L |
| Electronegativity (Pauling) | 3 |
| Electron affinity | -96 kJ/mol |
| Ionization energies | 1350.8, 2350.4, 3565 kJ/mol (1st, 2nd, 3rd) |
| Discovered by | William Ramsay |
Use the atomic mass in the molar mass calculator for any formula containing Kr.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of krypton?
The atomic mass of krypton is 83.798 u, so one mole of krypton atoms weighs 83.798 g.
What is the electron configuration of krypton?
Krypton has 36 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶, or [Ar] 3d¹⁰ 4s² 4p⁶ in noble-gas notation. Electrons per shell: 2, 8, 18, 8.
How many valence electrons does krypton have?
Krypton has 8 valence electrons (group 18).
Is krypton a metal?
No. Krypton is a nonmetal (noble gas).
Where is krypton on the periodic table?
Krypton is in group 18 (noble gases), period 4, in the p-block.
Data: 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.