Cesium

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 (83.3°F), which makes it one of only five elemental metals that are liquid at or near room temperature.

Physical Properties

• Symbol: Cs
• Atomic Number: 55
• Atomic Mass: 132.91 u
• Melting Point: 28.5°C (83.3°F)
• Boiling Point: 671°C (1,240°F)
• Density: 1.93 g/cm³

Chemical Properties

Cesium is highly reactive and is considered one of the most reactive elements. It reacts explosively with water, producing cesium hydroxide and hydrogen gas. It also reacts with air, forming a layer of cesium oxide on its surface.

Common Uses

Cesium is used in various applications, including atomic clocks, drilling fluids in the petroleum industry, and in the production of glass. It is also used in the production of photoelectric cells and as a catalyst in organic synthesis.

Study Guide

1. What is the symbol for cesium?
2. What is the atomic number of cesium?
3. What is the melting point of cesium?
4. Why is cesium considered one of the most reactive elements?
5. What are some common uses of cesium?

[Cesium] Related Worksheets and Study Guides:

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