Mendeleev
Periodic table · chemistry · physics
Element story

Arsenic

Atomic number 33 means that every Arsenic nucleus contains 33 protons. That proton count is the element's identity: change it and you no longer have Arsenic.

Start with the nucleus

Atomic number 33 means that every Arsenic nucleus contains 33 protons. That proton count is the element's identity: change it and you no longer have Arsenic.

Arsenic (As) is chemical element 33. It belongs to the metalloids, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.

In practice, it turns up most often in semiconductors, alloys and wood preservation.

See the atom

Conceptual visual: electron shells are a learning aid, not a literal picture of quantum orbitals.

What this number means

Atomic number 33 means that every Arsenic nucleus contains 33 protons. That proton count is the element's identity: change it and you no longer have Arsenic.

Keep exploring

→ Arsenic · Atomic structure · Periodic trends

33AsArsenic
Arsenic · As · Z = 33

Arsenic (As) is chemical element 33. It belongs to the metalloids, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.

Understanding the element

Arsenic (As) is chemical element 33. It belongs to the metalloids, 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 semiconductors, alloys and wood preservation.

What its position in the table tells us

Arsenic sits in period 4, group 15 and the P block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.