Symbol He
Atomic Number 2
Atomic Mass 4.003
Discovered by Helium was discovered by Sir William Ramsay in London, and independently by Per Teodor Cleve and Nils Abraham Langlet in Uppsala, Sweden.

Chemical Properties of Helium

Group 18 Melting point Unknown
Period 1 Boiling point −268.928°C, −452.07°F, 4.222 K
Block s Density (g cm−3) 0.000164
Atomic number 2 Relative atomic mass 4.003  
State at 20°C Gas Key isotopes 4He
Electron configuration 1s2 CAS number 7440-59-7
ChemSpider ID 22423 ChemSpider is a free chemical structure database

What is Helium?

  • Helium is the element which you can find on the upper right side of the periodic table with atomic number 2. It comes first amongst the family of the noble gases. It holds one atomic orbital and was named by Lockyer and Frankland. Its name is derived from the Greek word “Helios” meaning Sun. Scientists knew there is an enormous amount of helium in the Sun before it was discovered.
  • Helium falls under inert gas since its outermost electron orbital is full with two electrons. Helium can also be found in lasers, compressed air tanks and coolant in nuclear reactors. It holds the lowest boiling and melting points among the all other elements. The Nuclear fusion of hydrogen in stars generates a significant amount of helium.

Uses of Helium

  • The primary use of Helium goes in altitudes research and meteorological balloons.
  • It is utilized as an inert protective gas in autogenous welding.
  • It is the only cooler capable of declining temperature lower than 15K (-434ºF).
  • Ultralow temperature is main application is the development of superconductivity state wherein the resistance to electricity flux is almost next to zero.

Practise This Question

Assume that Millikan performed the oil drop experiment. In the oil drop experiment, the following charges(in arbitrary units) were found on a series of oil droplets. Calculate the magnitude of the charge on the electron.