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55 Cs
Element Revision Sheet

Caesium (Cs)

Alkali Metals Block S Group 1 • Period 6
Superhero Identity

"Meet Caesium, the hyper-reactive speedster of the alkali metals, who uses its explosive power to keep the universe's most precise clocks ticking!"

A memorable persona to anchor Cs in your mind.

Density

1.93

Grams per cm³

Melting Point

28.5

Celsius (°C)

Atomic Radius

343

Radius (pm)

Everyday Connection

Daily Life Link

Ever use GPS? You're literally trusting Caesium for every turn, as it keeps your navigation spot-on!

Discovery & History

Year Discovered

1860

Discovered By

Robert Bunsen & Gustav Kirchhoff

Origin of Name

"The name comes from the Latin 'caesius', meaning sky blue, and derived from its flame colour."

Technical Properties

Atomic Mass

132.905 u

Standard State

solid

Boiling Point

671°C

Electron Configuration

[Xe] 6s1

1st Ionization Energy

3.894 eV

Electron Affinity

N/A

Oxidation States

[+1]
Appearance

"Shimmering golden-silver, so soft you could cut it with a butter knife!"

Did You Know?

1

The ultimate water-hater! Drop a tiny piece of Caesium in water, and BOOM – it explodes with incredible force, even in ice-cold conditions!

2

It's the 'Master Timekeeper' – atomic clocks using Caesium are so incredibly accurate, they only lose about one second every 30 million years. That's precision on another level!

3

Forget ice cubes, how about metal melting in your hand? Caesium melts at just 28.5 °C (83.3 °F), meaning your body heat is enough to turn this solid metal into a shiny, golden liquid!

4

Unlike its dull grey cousins, Caesium rocks a unique silvery-gold sheen, making it stand out in the alkali metal family.

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