Helium is a noble gas and its symbol is He. It is a colorless, odorless and tasteless gas and it is also known as an inert gas. The atomic number of helium is 2 and its atomic mas is 4. Helium belong to the s block of the periodic table. Helium lies in 18th group and 1st period of the periodic table. The electronic configuration of helium atom is 1s2. It has two electrons. The outer most shell of a helium atom is completed. So, helium is stable and present as a mono-atomic gas. When a helium atom loses electrons, it get positive charge because the number of protons in the helium atom becomes greater than the number of electrons. When helium atom loses one electron it becomes positive ion with +1 charge. Moreover, when it loses two electrons, its become positive ion with +2 charge on it.