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Understanding the element
Caesium (Cs) is chemical element 55. It belongs to the alkali metals, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.
Where do we encounter it?
In practice, it turns up most often in atomic clocks, drilling fluids and scientific research.
atomic clocksdrilling fluidsscientific research
Standard atomic weight132.90545196(6)
What its position in the table tells us
Caesium sits in period 6, group 1 and the S block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.
Worth remembering
Caesium has a characteristic place in the periodic table that helps explain both its chemistry and its practical uses
Caesium has a characteristic place in the periodic table that helps explain both its chemistry and its practical uses