One atom of helium has two protons in its nucleus. A neutral atom of helium also has two electrons.
The number of protons in an element is equal to the element's atomic number. Helium has the atomic number 2, which means it has two protons. An element's atomic number appears directly above its symbol in some versions of the periodic table. In other versions, it appears in the top left corner of the element's square.
Helium was discovered by Sir William Ramsay in 1895. Its name is derived from the Greek word for "sun." This gas is found in the air, as well as in natural gas deposits.