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Periodic table · chemistry · physics
Element story

Rubidium

Atomic number 37 means that every Rubidium nucleus contains 37 protons. That proton count is the element's identity: change it and you no longer have Rubidium.

Start with the nucleus

Atomic number 37 means that every Rubidium nucleus contains 37 protons. That proton count is the element's identity: change it and you no longer have Rubidium.

Rubidium (Rb) is chemical element 37. 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 scientific research, atomic clocks and photocells.

See the atom

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

What this number means

Atomic number 37 means that every Rubidium nucleus contains 37 protons. That proton count is the element's identity: change it and you no longer have Rubidium.

Keep exploring

→ Rubidium · Atomic structure · Periodic trends

37RbRubidium
Rubidium · Rb · Z = 37

Rubidium (Rb) is chemical element 37. 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

Rubidium (Rb) is chemical element 37. 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 scientific research, atomic clocks and photocells.

What its position in the table tells us

Rubidium sits in period 5, group 1 and the S block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.