Mendeleev
Periodic table · chemistry · physics
Element story

Fermium

Atomic number 100 means that every Fermium nucleus contains 100 protons. That proton count is the element's identity: change it and you no longer have Fermium.

Start with the nucleus

Atomic number 100 means that every Fermium nucleus contains 100 protons. That proton count is the element's identity: change it and you no longer have Fermium.

Fermium (Fm) is chemical element 100. It belongs to the actinoids, 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.

See the atom

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

What this number means

Atomic number 100 means that every Fermium nucleus contains 100 protons. That proton count is the element's identity: change it and you no longer have Fermium.

Keep exploring

→ Fermium · Atomic structure · Periodic trends

100FmFermium
Fermium · Fm · Z = 100

Fermium (Fm) is chemical element 100. It belongs to the actinoids, 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

Fermium (Fm) is chemical element 100. It belongs to the actinoids, 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.

What its position in the table tells us

Fermium sits in period 7 and the F block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.