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36 Kr
Element Revision Sheet

Krypton (Kr)

Noble Gases Block P Group 18 • Period 4
Superhero Identity

"The Hidden Hero, an elusive and noble hero, often mistaken for a superhero's one weakness."

A memorable persona to anchor Kr in your mind.

Density

3.749

Grams per cm³

Melting Point

-157.37

Celsius (°C)

Atomic Radius

202

Radius (pm)

Everyday Connection

Daily Life Link

Krypton is found in the high-intensity gas inside an airport runway light.

Discovery & History

Year Discovered

1898

Discovered By

William Ramsay & Morris Travers

Origin of Name

"The name is derived from the Greek ''kryptos'', meaning hidden."

Technical Properties

Atomic Mass

83.798 u

Standard State

gas

Boiling Point

-153.415°C

Electron Configuration

[Ar] 3d104s24p6

1st Ionization Energy

14 eV

Electron Affinity

N/A

Oxidation States

[0]
Appearance

"Krypton is a colorless, odorless, tasteless inert gas."

Did You Know?

1

Its name comes from the Greek word 'kryptos', meaning 'the hidden one', because it was difficult to find and isolate.

2

Krypton is famously associated with Superman's home planet, although the real element has no connection to the comic book hero.

3

From 1960 to 1983, the official length of a meter was defined in terms of the wavelength of light emitted by krypton-86 atoms.

4

When an electric current is passed through krypton gas, it produces a smoky-white light, which is used in high-powered "halogen" headlights and photographic flashes.

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