A chemical element represents a fundamental substance that cannot be broken down into simpler substances through typical chemical reactions. Each element is uniquely identified by the number of protons in its atomic nucleus, a value known as its atomic number. While many elements occur naturally on Earth, a distinct group has been created by scientists. These human-made elements extend the known boundaries of matter.
Defining Synthetic Elements
Synthetic elements are chemical elements that do not exist naturally on Earth or appear only in extremely minute, transient quantities. Scientists produce them artificially by manipulating fundamental particles in specialized laboratory settings.
A defining characteristic of synthetic elements is their inherent instability and radioactivity. This means their atomic nuclei are not stable and undergo radioactive decay, transforming into other elements over time. Consequently, synthetic elements typically possess very short half-lives, ranging from fractions of a second to, in some cases, millions of years, which is still brief compared to Earth’s geological age.
Counting the Synthetic Elements
Currently, there are 24 recognized synthetic elements, which are those with atomic numbers from 95 to 118. These elements were first created in laboratories between 1944 and 2010.
Five other elements, namely technetium (atomic number 43), promethium (atomic number 61), astatine (atomic number 85), neptunium (atomic number 93), and plutonium (atomic number 94), were initially synthesized before trace amounts were later discovered in nature. While sometimes grouped with synthetic elements due to their artificial production, their natural occurrence distinguishes them from those exclusively made by humans. All synthetic elements, along with neptunium and plutonium, are classified as transuranic elements, meaning they possess an atomic number greater than uranium (atomic number 92).
Creating Synthetic Elements
Scientists create synthetic elements primarily through nuclear reactions within specialized facilities like particle accelerators or nuclear reactors. One common method involves accelerating lighter atomic nuclei to extremely high speeds and then smashing them into heavier target nuclei. This high-energy collision can cause the nuclei to fuse, forming a new, heavier element.
For elements with lower atomic numbers, a different approach involves bombarding heavy elements, such as uranium or plutonium, with neutrons in a nuclear reactor. This bombardment can lead to neutron capture and subsequent beta decay, increasing the atomic number and creating new elements.
The Significance of Synthetic Elements
The creation of synthetic elements advances the understanding of nuclear physics and the fundamental nature of matter. By extending the periodic table beyond naturally occurring elements, scientists gain insights into the forces that hold atomic nuclei together and the potential limits of element existence. This research helps test and refine theoretical models of atomic structure.
Most synthetic elements are too unstable and short-lived for practical applications. However, their synthesis is important for fundamental research. Some earlier synthetic elements, like americium, have found limited use in devices such as smoke detectors. The ongoing quest to synthesize new, heavier elements expands scientific knowledge, even if immediate practical uses are not apparent.