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Element Revision Sheet

Promethium (Pm)

Lanthanoids Block F Group Lanthanides • Period 6
Superhero Identity

"Promethium is the elusive Light-Bringer, radiating a steady, powerful glow from within, empowering the darkest corners with its unique energy!"

A memorable persona to anchor Pm in your mind.

Density

7.26

Grams per cm³

Melting Point

1042

Celsius (°C)

Atomic Radius

236

Radius (pm)

Everyday Connection

Daily Life Link

Think of those glow-in-the-dark stickers on your ceiling, but way more powerful and for serious tech!

Discovery & History

Year Discovered

1945

Discovered By

Jacob A. Marinsky, Lawrence E. Glendenin & Charles D. Coryell

Origin of Name

"Promethium is named after Prometheus of Greek mythology who stole fire from the Gods and gave it to humans."

Technical Properties

Atomic Mass

[145] u

Standard State

solid

Boiling Point

3000°C

Electron Configuration

[Xe] 4f56s2

1st Ionization Energy

5.55 eV

Electron Affinity

N/A

Oxidation States

[+3]
Appearance

"A soft, silvery-metallic glint, but don't get too close – it's always buzzing with energy!"

Did You Know?

1

Promethium is so rare it was predicted *before* it was officially discovered! Scientists noticed a gaping hole for element 61 in the periodic table years earlier.

2

It's named after Prometheus, the Greek Titan who famously stole fire from the gods and gave it to humanity – a perfect name for an element that literally 'shines' with its own internal energy!

3

Promethium is one of only two elements in the first 82 on the Periodic Table that has absolutely NO stable isotopes. Every single Promethium atom is a ticking radioactive clock!

4

You won't find Promethium veins in a mine! It's virtually absent from Earth's crust in natural quantities, primarily formed as a byproduct when heavier elements like Uranium split apart.

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