Helium: Study Guide

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:

• Symbol: He
• Atomic Number: 2
• Atomic Mass: 4.0026 amu
• Phase at Room Temperature: Gas
• Boiling Point: -268.9°C
• Melting Point: -272.2°C
• Density: 0.1786 g/L

Uses of Helium:

Helium has several important applications, including:

• Used as a coolant for nuclear reactors and to cool the superconducting magnets in magnetic resonance imaging (MRI) machines.
• Used in the production of semiconductor devices and fiber optics.
• Used in gas chromatography and as a carrier gas in gas chromatography-mass spectrometry.
• Used to fill balloons and airships due to its low density and non-flammability.

Chemical 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.

Study Tips for Helium:

When studying helium, it's important to focus on its unique properties, uses, and its place in the periodic table. Understanding its low boiling and melting points, as well as its inert nature, can help in comprehending its diverse applications. Additionally, understanding its abundance in the universe and its unique role in various technological and scientific processes is crucial for a comprehensive understanding of the element.