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93 Np
Element Revision Sheet

Neptunium (Np)

Actinoids Block F Group Actinides • Period 7
Superhero Identity

"The Guardian of the Atomic Abyss, silently radiating its formidable power, a crucial stepping stone to unlocking even greater elemental forces."

A memorable persona to anchor Np in your mind.

Density

20.45

Grams per cm³

Melting Point

644

Celsius (°C)

Atomic Radius

221

Radius (pm)

Everyday Connection

Daily Life Link

Like the super-rare, hidden ingredient in a cutting-edge, high-tech formula, essential for creating something far more powerful that you DO hear about.

Discovery & History

Year Discovered

1940

Discovered By

Edwin McMillan & Philip H. Abelson

Origin of Name

"Neptunium was named after the planet Neptune."

Technical Properties

Atomic Mass

[237] u

Standard State

solid

Boiling Point

3902°C

Electron Configuration

[Rn] 5f46d17s2

1st Ionization Energy

6.266 eV

Electron Affinity

N/A

Oxidation States

[+6 +5 +4 +3]
Appearance

"A shiny, silvery metal that quickly tarnishes in air, hinting at its powerful, reactive nature."

Did You Know?

1

First Transuranic Element! Neptunium (Np) isn't just any element; it was the *first* transuranic element ever synthesized! That means it's heavier than Uranium, the heaviest element naturally found on Earth in significant amounts. Mind = blown!

2

Named After a Cosmic Giant. Following the celestial theme of Uranium (named after Uranus), Neptunium takes its name from Neptune, the distant, majestic eighth planet in our solar system. Talk about stellar naming!

3

A Human-Made Marvel. Don't go digging for Neptunium in your backyard; it's a synthetic element, meaning we primarily create it! Most of it comes from nuclear reactors, where neutrons bombard uranium atoms.

4

Plutonium's Secret Ingredient. Neptunium plays a crucial, behind-the-scenes role. It's often an intermediate step in the creation of Plutonium-239, a heavy hitter used in nuclear power and advanced technology.

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