Uranium is element number 92, with the symbol U. Its name comes from Uranus, the god of the sky in Greek myth, and the planet named after him.
Atomic number 92238.0
UUraniumウラン (uran)
Symbol
U
Atomic weight
238.0
Place in the table
Period 7 · Actinoids
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
The sky god and the planet Uranus
Uranium was discovered in 1789 and named after the planet Uranus.
Neptunium (Neptune) and plutonium (Pluto), found later, follow uranium in the order of the planets’ names.
Where it sits on the table
The fifteen elements from actinium to lawrencium are called the actinoids. On the Room of the Elements table they are in the lower of the two rows set apart at the bottom.
Think about it
Q1Why do you think uranium, neptunium and plutonium line up in the order Uranus, Neptune, Pluto?
Q2How many elements named after heavenly bodies can you find?
Q3Which actinoid was discovered earliest?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — Elements 92, 93 and 94 are named after Uranus, Neptune and Pluto, lined up in number order.