Cesium: Properties and Uses

Cesium is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28.5°C, making it one of only five elemental metals that are liquid at or near room temperature. Here are some key points to remember about cesium:

• Atomic number: 55
• Symbol: Cs
• Group: Alkali metal
• Physical state at room temperature: Liquid
• Melting point: 28.5°C
• Boiling point: 671°C

Properties of Cesium

Cesium is highly reactive and is stored and shipped in sealed containers to prevent its reaction with air and water. It is the most alkaline of the elements and readily forms compounds with oxygen and other non-metallic elements. Cesium also has the lowest ionization potential of all stable elements, making it an important component in photoelectric cells and atomic clocks.

Uses of Cesium

Cesium has a few important uses, including:

1. Atomic clocks: Cesium is used as the reference for the definition of the second in the International System of Units (SI).
2. Photoelectric cells: Cesium is used in photoelectric cells and other photoelectric devices due to its low ionization potential.
3. Drilling fluids: Cesium formate is used in the petroleum industry as a high-density drilling fluid to prevent blowouts in oil and gas wells.

Study Guide

To study cesium effectively, make sure to understand the following key points:

1. The atomic number and symbol of cesium.
2. The physical state of cesium at room temperature.
3. The properties of cesium, including its reactivity and ionization potential.
4. The uses of cesium in atomic clocks, photoelectric cells, and drilling fluids.

Additionally, be prepared to explain the significance of cesium in the International System of Units (SI) and its role in defining the second.

[Cesium] Related Worksheets and Study Guides:

• Elements and the periodic tableScience • Seventh Grade
• Elements, mixtures and compoundsScience • Fifth Grade