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Periodic table · chemistry · physics
Element story

Sodium

Atomic number 11 means that every Sodium nucleus contains 11 protons. That proton count is the element's identity: change it and you no longer have Sodium.

Start with the nucleus

Atomic number 11 means that every Sodium nucleus contains 11 protons. That proton count is the element's identity: change it and you no longer have Sodium.

Sodium (Na) is chemical element 11. 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.

In practice, it turns up most often in common salts, chemical synthesis and reactor coolant.

See the atom

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

What this number means

Atomic number 11 means that every Sodium nucleus contains 11 protons. That proton count is the element's identity: change it and you no longer have Sodium.

Keep exploring

→ Sodium · Atomic structure · Periodic trends

11NaSodium
Sodium · Na · Z = 11

Sodium (Na) is chemical element 11. 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.

Understanding the element

Sodium (Na) is chemical element 11. 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 common salts, chemical synthesis and reactor coolant.

What its position in the table tells us

Sodium sits in period 3, group 1 and the S block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.