Californium
Definition and meaning of Californium in chemistry.
![Californium element card: symbol Cf, atomic number 98, atomic mass [251], electron configuration [Rn] 5f¹⁰ 7s², oxidation states +3, Actinide, f-block, period 7, solid at room temperature.](/assets/images/terms/californium-chemical-element.webp)
Californium is a human-made radioactive metal with the symbol Cf and atomic number 98. It belongs to the actinide series of heavy metals at the bottom of the periodic table. Scientists value this element because it is a very strong source of neutrons.
In more detail
Californium is a silvery metal that slowly tarnishes when exposed to room temperature air. The solid metal reacts quickly with oxygen, steam, and acids. Scientists make it by bombarding lighter elements like curium with neutrons inside nuclear reactors.
This production process takes several years and yields only small amounts of the element. Californium usually exists in the +3 oxidation state when it forms chemical compounds. Scientists have also produced solid compounds with a rare +2 oxidation state.
A common student misconception is that we cannot see human-made elements. In fact, californium is the heaviest element that scientists have produced in visible amounts. Its most common isotope is californium-252, which undergoes spontaneous fission.
Fission is a chemical process where an unstable atomic nucleus splits into smaller parts. During fission, the nucleus releases a high number of free neutrons. Because of this intense neutron radiation, californium is highly hazardous to living tissue. A single gram of this material costs millions of dollars to produce due to the complexity.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Cf |
| Atomic number | 98 |
| Atomic mass | [251] u |
| Category | Actinide |
| Notable property | Spontaneously emits neutrons |
Engineers use californium-252 in downhole tools to analyze soil and rock formations around oil wells. The tool shoots neutrons into the ground to detect hydrogen atoms in water and oil. By measuring the returned signals, workers can map the contents of the well. This helps energy companies find valuable oil deposits deep underground without digging unnecessary test holes. The high cost of californium is balanced by the massive savings it provides during drilling.
Frequently asked questions
Why is californium so expensive to produce?
It requires starting materials like plutonium, which must absorb neutrons over many years inside a reactor. The chemical separation process is also extremely difficult and dangerous.
Can californium be used in cancer treatments?
Yes, doctors use californium-252 as a source of neutrons for cancer therapy. They insert tiny sources directly into tumors to destroy cancer cells from the inside.
What is spontaneous fission in californium-252?
Spontaneous fission is a type of decay where the nucleus splits without any outside trigger. This process releases massive energy and a steady stream of fast neutrons.
Related terms
Sources & references
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