Helium has an atomic mass of
(A) 4.0026
(B) 6
© 4
(D) 2

Helium, known for being the second lightest element in the universe, has an atomic mass of approximately 4.0026 amu (atomic mass units). This value reflects the weighted average of all isotopes of helium, predominantly helium-4, which contains two protons and two neutrons, giving it its low mass and making it ideal for use in balloons and cooling applications.

In real-world applications, helium is not just a party balloon staple; it has critical uses in various fields. For instance, it plays an essential role in cooling superconducting magnets in MRI machines and is utilized in cryogenics, which helps with the preservation of biological specimens. Its non-reactive nature and low boiling point make it a unique element in both scientific and commercial contexts.