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85 At
Element Revision Sheet

Astatine (At)

Halogens Block P Group 17 • Period 6
Superhero Identity

"The Ghostly Tracer: A super-speedy, almost mythical hero who leaves a radioactive fingerprint, here and gone in a blink."

A memorable persona to anchor At in your mind.

Density

7

Grams per cm³

Melting Point

300

Celsius (°C)

Atomic Radius

202

Radius (pm)

Everyday Connection

Daily Life Link

As fleeting and rare as spotting a shooting star in broad daylight.

Discovery & History

Year Discovered

1940

Discovered By

Dale R. Corson, Kenneth R. MacKenzie & Emilio Segrè

Origin of Name

"The name comes from the Greek ''astatos'', meaning unstable."

Technical Properties

Atomic Mass

[210] u

Standard State

solid

Boiling Point

350°C

Electron Configuration

[Xe] 4f145d106s26p5

1st Ionization Energy

9.5 eV

Electron Affinity

N/A

Oxidation States

[7 5 3 1 -1]
Appearance

"A dark, possibly metallic solid, but good luck getting a glimpse!"

Did You Know?

1

Forget finding a needle in a haystack; finding Astatine in nature is like finding a specific atom in the entire universe – it's the *rarest naturally occurring element* on Earth!

2

Its name is a total spoiler! 'Astatine' comes from the Greek word 'astatos,' literally meaning 'unstable' – and believe me, it lives up to its name!

3

Every single Astatine isotope is a speed demon of decay! Its most stable isotope, Astatine-210, still has a half-life of only 8.1 hours – that's lightning fast in the element world!

4

Hold onto your protons: at any given moment, the *entire Earth's crust* contains less than 28 grams (about one ounce) of naturally occurring Astatine! That's less than a single chocolate bar!

Ready to Test Your Knowledge?