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Basic Information

Name: Helium
Symbol: He
Atomic Number: 2
Atomic Mass: 4.002602 amu
Melting Point: -272.0 °C (1.15 K, -457.6 °F)
Boiling Point: -268.6 °C (4.549994 K, -451.48 °F)
Number of Protons/Electrons: 2
Number of Neutrons: 2
Classification: Noble Gas
Crystal Structure: Hexagonal
Density @ 293 K: 0.1785 g/cm³
Color: colorless

Atomic Structure

Number of Energy Levels: 1

First Energy Level:

Isotopes

Isotope	Half Life
He-3	Stable
He-4	Stable

Facts

Date of Discovery: 1895
Discoverer: Sir William Ramsay
Name Origin: From the Greek word h�lios (sun)
Uses: balloons, deep sea diving
Obtained From: natural gas deposit, air

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