Helium

Statistics:

• Name: Helium
• Symbol: He
• Classification: Noble Gas
• Atomic Number: 2
• Atomic Mass: 4.002602 g/mol
• Density: 0.17 g/cm³
• Melting: -272.2°C
• Boiling: -268.9°C
• Protons & Electrons:2
• Neutrons:2
• Discovered: 1895
• Discovered By: Ramsay and Cleve
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Electrons Per Energy Level:

• Level 1: 2

Isotopes:

Isotope: Half-life

• ³He: stable
• ⁴He: stable

Brief Summary

Helium is a Noble Gas with the symbol 'He' and contains 2 Protons & Electrons with 2 neutrons in the nucleus of the atom. Helium has an atomic mass of 4.002602 g/mol and, at a temperature of 20°C, has a density of 0.17 g/cm³. It will melt at a temperature of -272.2°C and boil at -268.9°C.

Helium was discovered by Ramsay and Cleve in 1895 and is named 'Helium' From the Greek word hêlios (sun).

Some common usages for Helium: balloons, deep sea diving.

Definitions and Notes

Density listed is at a temperature of 20°C.

Isotopes are forms of an element who have the same atomic number but different mass because they contain different number of neutrons.

Half-life is the time required for a quantity of a subject to fall to half of its current quantity.

MLA Citing Format

Helium :: He :: 2 - Chemical Element. 22 Nov. 2008 <http://www.chemicalelement.com/element/helium.html>.