Californium is element number 98, with the symbol Cf. Its name comes from the state of California in the United States.
Atomic number 98(252)
CfCaliforniumカリホルニウム (karihoruniumu)
Symbol
Cf
Atomic weight
(252)
Place in the table
Period 7 · Actinoids
The number in parentheses is not an atomic weight. It is the mass number of one radioactive isotope of the element.
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
A state’s name
Californium was discovered in 1950 and named after California, following berkelium (Berkeley) the year before.
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
Q1Where in the United States is California?
Q2Why might elements found one after another be named after the same region?
Q3Can you name three elements linked to America?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — Element names linked to America: americium (1945), berkelium (1949) and californium (1950).