Helium

Number of Energy Levels: 1
First Energy Level: 2
He Helium

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

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