Mendeleev
Periodic table · chemistry · physics
Element story

Fluorine

Atomic number 9 means that every Fluorine nucleus contains 9 protons. That proton count is the element's identity: change it and you no longer have Fluorine.

Start with the nucleus

Atomic number 9 means that every Fluorine nucleus contains 9 protons. That proton count is the element's identity: change it and you no longer have Fluorine.

Fluorine (F) is chemical element 9. It belongs to the halogens, and its reference state at room temperature is a gas. Those basic facts are a useful starting point for its chemistry and applications.

In practice, it turns up most often in fluoropolymers, dental fluorides and uranium chemistry.

See the atom

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

What this number means

Atomic number 9 means that every Fluorine nucleus contains 9 protons. That proton count is the element's identity: change it and you no longer have Fluorine.

Keep exploring

→ Fluorine · Atomic structure · Periodic trends

9FFluorine
Fluorine · F · Z = 9

Fluorine (F) is chemical element 9. It belongs to the halogens, and its reference state at room temperature is a gas. Those basic facts are a useful starting point for its chemistry and applications.

Understanding the element

Fluorine (F) is chemical element 9. It belongs to the halogens, 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 fluoropolymers, dental fluorides and uranium chemistry.

What its position in the table tells us

Fluorine sits in period 2, group 17 and the P block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.