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Helium (He)
Element with atomic number 2, category: Noble gas, a gas at room temperature.
Element 2 of 118
Noble gas
Helium
Group 18, Period 1
Common Uses
Balloons, MRI coolant
Electron Diagram
About Helium
Helium is a chemical element with the symbol He and atomic number 2, meaning every atom has 2 protons in its nucleus. It is classed as Noble gas and is a gas at room temperature. Its atomic mass is about 4.003 atomic mass units (u).
On the periodic table, Helium sits in group 18, period 1, which determines how many electron shells it has and how it tends to react with other elements.
Uses of Helium
In daily life and industry, Helium is used for Balloons, MRI coolant. These uses are closely tied to the typical properties of elements in the Noble gas category.
Electron Structure of Helium
Using a simplified electron shell model (at most 2 electrons in the first shell, 8 in the second, 18 in the third, and so on), Helium has 1 electron shells, with an approximate arrangement of 2 electrons from the innermost shell to the outermost. This is a simplified learning model, not the full electron configuration that accounts for the s, p, d and f subshells.
Explore Other Elements
Want to see another element or try the element symbol quiz? Go back to the Interactive Periodic Table to explore all 118 chemical elements.