Helium
Helium is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table.
Physical Properties
Helium is the second lightest element and is the second most abundant element in the observable universe, being present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined.
At standard temperature and pressure, helium exists as a gas. It has the lowest boiling point of all the elements, and it remains liquid down to absolute zero at normal pressures.
Chemical Properties
Helium is the least reactive noble gas, and it does not form chemical compounds under normal conditions. It is, however, a key component in the formation of stars and is present in the Earth's atmosphere in trace amounts.
Uses
Helium is widely used as a lifting gas in balloons and airships. It is also used in cryogenics, as a coolant for superconducting magnets in MRI machines and other medical equipment. Additionally, helium is used in the aerospace industry and in diving to dilute the oxygen and nitrogen content of breathing gases.
Study Guide
- What is the atomic number of helium?
- Explain the physical properties of helium.
- Why is helium used in cryogenics?
- Discuss the chemical properties of helium.
- Describe the uses of helium in various industries.
