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Understanding the element
Helium (He) is chemical element 2. It belongs to the noble gases, and its reference state at room temperature is a gas. 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 balloons, medical imaging equipment and cryogenics.
balloonsmedical imaging equipmentcryogenics
Standard atomic weight4.002602(2)
What its position in the table tells us
Helium sits in period 1, group 18 and the S block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.
Worth remembering
Helium has a characteristic place in the periodic table that helps explain both its chemistry and its practical uses
Helium has a characteristic place in the periodic table that helps explain both its chemistry and its practical uses