---
title: "Krypton (Kr): Atomic Mass, Electron Configuration & Properties"
url: https://www.moldraw.com/elements/krypton.html
description: "Krypton (Kr), element 36: atomic mass 83.798, electron configuration [Ar] 3d¹⁰ 4s² 4p⁶, group 18, period 4, p-block noble gas. Melting and boiling point, density, electronegativity and shells."
lang: en
publisher: Scidart Academy
generated: 2026-11-03
---
36Kr83.798

# 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.

[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)

## 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](https://www.moldraw.com/tools/free-chem-tools/electron-configuration-calculator.html).

## 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](https://www.moldraw.com/tools/free-chem-tools/molar-mass-calculator.html) for any formula containing Kr.

## Position in the periodic table

Tap any element to open its page.

## 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](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.