What is 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. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.

Properties of Helium:

• Atomic Number: 2
• Symbol: He
• Atomic Mass: 4.0026 u
• Phase at Room Temperature: Gas
• Boiling Point: -268.9°C
• Melting Point: -272.2°C
• Density: 0.1785 g/L
• State of Matter: It exists as a gas at room temperature and pressure.

Uses of Helium:

Helium has several important uses, including:

• As a coolant for nuclear reactors and to cool the superconducting magnets in MRI machines.
• In gas chromatography and as a carrier gas for other analytical instruments.
• In gas mixtures for deep-sea diving to prevent nitrogen narcosis.
• As a lifting gas in balloons and airships due to its low density.

Helium's Role in the Universe:

Helium is the second most abundant element in the observable universe, after hydrogen. It is produced by the nuclear fusion of hydrogen in stars and is present in the sun and other stars as well as in the atmospheres of gas giant planets such as Jupiter and Saturn.

Study Guide:

Here are some key points to remember when studying helium:

1. What is the atomic number and symbol of helium?
2. What are the physical properties of helium?
3. What are the major uses of helium?
4. How is helium produced in the universe?

Understanding the properties and uses of helium is important in various scientific and industrial applications. Remembering the key points and applications will help you grasp the significance of this element in our daily lives and the universe as a whole.