Mendeleev
Periodic table · chemistry · physics
Element story

Neptunium

Atomic number 93 means that every Neptunium nucleus contains 93 protons. That proton count is the element's identity: change it and you no longer have Neptunium.

Start with the nucleus

Atomic number 93 means that every Neptunium nucleus contains 93 protons. That proton count is the element's identity: change it and you no longer have Neptunium.

Neptunium (Np) is chemical element 93. 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 and nuclear science.

See the atom

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

What this number means

Atomic number 93 means that every Neptunium nucleus contains 93 protons. That proton count is the element's identity: change it and you no longer have Neptunium.

Keep exploring

→ Neptunium · Atomic structure · Periodic trends

93NpNeptunium
Neptunium · Np · Z = 93

Neptunium (Np) is chemical element 93. 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

Neptunium (Np) is chemical element 93. 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 and nuclear science.

What its position in the table tells us

Neptunium 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.