4
Be
Alkaline earth metal

Beryllium

Atomic number 4 · Period 2 · Block S

Be · Beryllium
Mendeleev.com

Understanding the element

Beryllium (Be) is chemical element 4. It belongs to the alkaline-earth 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 aerospace, X-ray windows and alloys.

aerospaceX-ray windowsalloys
Standard atomic weight9.0121831(5)

What its position in the table tells us

Beryllium sits in period 2, group 2 and the S block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.

Worth remembering
Beryllium has a characteristic place in the periodic table that helps explain both its chemistry and its practical uses

Scientific sources

Element identity
Atomic number4
Group2
Period2
BlockS
CategoryAlkaline earth metal
PhaseSolid