1. cesium
Cesium, Chinese characters, metal elements, symbol Cs. Silver-white, soft, very active in chemical properties, easy to release electrons under the action of light and explode when it meets water. Used for photovoltaic cells and rocket propulsion.
2. Chemical elements
Cesium, element symbol Cs, atomic number 55, located in the sixth cycle, belongs to family IA. Its simple substance is a light golden active metal with low melting point, which is easily oxidized in air and can react violently with water to produce hydrogen and explode.
Cesium has no elemental form in nature and is rarely distributed on land and sea in the form of salt. Cesium is an important material for manufacturing vacuum devices and photovoltaic cells. Radionuclide Cs- 137 is one of the radioactive pollution leaked from the Fukushima Daiichi nuclear power plant in Japan. Cesium has the highest metal content among known elements (including radioactive elements).
Cesium, located in the sixth cycle of group IA, is a silver-gold alkali metal, which is very soft (its Mohs hardness is the lowest among all elements) and malleable. Cesium metal is not radioactive, but it is a dangerous chemical, which will ignite spontaneously when wet. Care should be taken when using.
The biological behavior of cesium is similar to that of potassium. After eating the biosoluble compound containing cesium-137 for 24 hours, cesium-137 can be fully absorbed by human body and combined with cells to produce internal irradiation.
Cesium-137 can be used as a gamma radiation source for radiation breeding, radiation storage of food, sterilization of medical instruments, treatment of cancer and gamma detection of industrial equipment. Due to the weakness of long half-life and easy diffusion of cesium source, cesium-137 source has been gradually replaced by cobalt -60 source.
Cesium is extremely active chemically. Cesium generates a layer of gray-blue oxide in the air, which can spontaneously ignite in less than one minute, emitting a deep purple flame and generating very complex cesium oxide.
Cesium is the most active among alkali metals, which can react violently with oxygen to produce various cesium oxides. In humid air, the heat of oxidation is enough to make cesium melt and burn. Cesium does not react with nitrogen, but can combine with hydrogenation at high temperature to form quite stable hydride. Cesium can react violently with water. If cesium is put into the water tank, it will explode immediately.