Atomic Number and the Creation of New Elements: From Discovery to Laboratory Synthesis

Atomic Number and
the Creation of New
Elements
From Discovery to Laboratory Synthesis

The Concept of Atomic Number
▪ The atomic number is the
number of protons in the
nucleus of an atom.
▪ Importance: Determines the
identity of the element.
▪ Introduced by: Henry Moseley
(1913), who showed that
atomic number, not atomic
mass, defines elements.

Atomic Number and the Periodic Table
▪ Organization: Elements are
arranged by increasing atomic
number.
▪ Prediction: Gaps in the table
suggested undiscovered
elements.
▪ Foundation: Allowed
scientists to predict properties
of new elements.

Laboratory Synthesis of Elements
▪ Process: Scientists bombard atomic
nuclei with particles (like neutrons or
smaller nuclei).
▪ Goal: Increase the number of protons
new atomic number new element.
→ →
▪ Example: Bombarding uranium with
neutrons produced neptunium (Z=93).

Examples of Synthetic Elements

Importance of Atomic Number in Synthesis
▪ Guides Experiments: Scientists
know how many protons are needed
for a new element.
▪ Predicts Properties: Atomic number
determines chemical behavior.
▪ Expands Knowledge: Led to
discovery of transuranium elements
(beyond uranium).

Modern Superheavy Elements
▪ Recent Discoveries:
Elements 114 (Flerovium),
118 (Oganesson).
▪ Significance: Pushes
boundaries of chemistry
and nuclear physics.

Atomic Number and the Creation of New Elements: From Discovery to Laboratory Synthesis