9
F
Halogen

Fluorine

Atomic number 9 · Period 2 · Block P

F · Fluorine
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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.

fluoropolymersdental fluoridesuranium chemistry
Standard atomic weight18.998403162(5)

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.

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

Scientific sources

Element identity
Atomic number9
Group17
Period2
BlockP
CategoryHalogen
PhaseGas