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2 He
Element Revision Sheet

Helium (He)

Noble Gases Block S Group 18 • Period 1
Superhero Identity

"Meet 'The Chill Whisperer,' the universe's ultimate light-as-air secret agent who lifts spirits (literally!) and chills out cutting-edge tech without ever making a fuss."

A memorable persona to anchor He in your mind.

Density

0.178

Grams per cm³

Melting Point

N/A

Celsius (°C)

Atomic Radius

140

Radius (pm)

Everyday Connection

Daily Life Link

Think of those floating party balloons that defy gravity and give you a hilarious squeaky voice.

Discovery & History

Year Discovered

1895

Discovered By

"Pierre Janssen, Norman Lockyer (Detection); Sir William Ramsay, Cleve, & Langlet (Isolation)"

Origin of Name

"The name is derived from the Greek, 'helios' meaning sun, as it was in the sun's corona that helium was first detected."

Technical Properties

Atomic Mass

4.003 u

Standard State

gas

Boiling Point

-268.928°C

Electron Configuration

1s2

1st Ionization Energy

24.587 eV

Electron Affinity

N/A

Oxidation States

[0]
Appearance

"It's an invisible, odorless, tasteless gas – you can't see it, smell it, or taste it, but you'll definitely feel its lift!"

Did You Know?

1

Mind-blowing fact: Helium was actually discovered in the Sun before it was found on Earth! Scientists spotted its unique spectral lines during a solar eclipse in 1868. Talk about an extraterrestrial find!

2

It's the second lightest element in the entire universe, just after hydrogen. That's why it's so good at making things float – it's practically weightless!

3

Helium is one of the 'noble gases,' meaning it's super unreactive. It doesn't like to bond with other elements, making it incredibly stable and aloof – the true introvert of the periodic table!

4

The classic helium voice isn't because it changes your vocal cords, but because it's so light! Sound travels faster through helium than air, shortening the resonant frequencies in your vocal tract, making your voice sound higher and squeakier.

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