The periodic table of elements, a cornerstone of chemistry and science education, organizes the known chemical elements in a meaningful and predictive way. But how many elements are actually on this table, and how did we come to know them all? The answer to “how many elements on the periodic table” isn’t just a simple number; it’s a story of scientific discovery, ongoing research, and a deeper understanding of the universe around us.
Currently, the periodic table officially recognizes 118 elements. These elements range from hydrogen, the lightest and most abundant element in the universe, to oganesson, the heaviest and most recently added element. Each of these elements possesses unique properties and plays a distinct role in the vast complexity of matter.
A Journey Through the Periodic Table: From Early Discoveries to Modern Science
The journey to identify and organize these 118 elements has been a long and fascinating one, evolving alongside our understanding of chemistry and physics. Early chemists worked to isolate and identify elements through experimentation, gradually piecing together the fundamental building blocks of matter.
Initially, the number of known elements was much smaller. Ancient civilizations were familiar with elements like gold, silver, copper, iron, and sulfur, which occur naturally in relatively pure forms. As scientific methods developed, particularly in the 18th and 19th centuries, the pace of element discovery accelerated. Scientists like Antoine Lavoisier and John Dalton laid the groundwork for modern chemistry, leading to the identification of elements like oxygen, nitrogen, and carbon.
The true breakthrough in understanding the elements came with Dmitri Mendeleev’s creation of the periodic table in 1869. Mendeleev organized the known elements based on their atomic weight and chemical properties, recognizing repeating patterns or “periods.” Crucially, Mendeleev’s table had gaps, spaces he predicted would be filled by elements yet to be discovered. This predictive power was dramatically confirmed as elements like gallium, scandium, and germanium were discovered and found to fit perfectly into Mendeleev’s framework.
A colorful depiction of the periodic table of elements, showcasing the arrangement of elements by atomic number and chemical properties.
Berkeley Lab’s Role in Expanding the Periodic Table
The quest to discover new elements didn’t stop with Mendeleev. In fact, the Lawrence Berkeley National Laboratory (Berkeley Lab) has played a pivotal role in expanding the periodic table, particularly in the 20th and 21st centuries. Berkeley Lab scientists have been credited with the discovery or co-discovery of 16 elements, a significant contribution to our understanding of matter.
One remarkable anecdote highlights this era of discovery. As recounted by Berkeley Lab, Glenn Seaborg, a Nobel laureate and key figure in element discovery, famously announced the discovery of two new elements (americium and curium) on a children’s radio show in 1945. This occurred because so many new elements were being found at the time, reflecting the intense scientific activity at Berkeley Lab and other research institutions.
Berkeley Lab’s contributions began earlier, however, with the discovery of technetium (element 43) in 1937. This element was particularly significant as it filled a predicted gap in Mendeleev’s table. Emilio Segrè, working with Ernest Lawrence at Berkeley Lab, identified technetium by bombarding molybdenum with deuterium. This demonstrated the power of using particle accelerators like cyclotrons to create new elements.
Berkeley Lab’s legacy extends to the realm of superheavy elements, those with atomic numbers beyond uranium (element 92). These elements are not found in nature and are created in laboratories through nuclear reactions. Berkeley Lab researchers have been instrumental in the discovery of elements like rutherfordium (104) and moscovium (115), pushing the boundaries of the periodic table and our understanding of nuclear physics.
Beyond Elements: Isotopes and Medical Applications
In addition to discovering new elements, Berkeley Lab has made significant contributions to the study of isotopes. Isotopes are variations of an element with the same number of protons but different numbers of neutrons. Berkeley Lab boasts credit for discovering over 630 isotopes, more than any other institution worldwide.
These radioisotopes have become invaluable tools in medicine. Berkeley Lab was a driving force in the development of nuclear medicine, and today, isotopes produced at Berkeley Lab and elsewhere are used for both diagnostic imaging and therapeutic treatments, particularly in cancer therapy. Researchers at Berkeley Lab continue to develop new methods for producing isotopes, including promising candidates like actinium-225 for targeted cancer treatment.
Ernest Lawrence with the cyclotron, a device crucial to Berkeley Lab’s discoveries of new elements and isotopes.
The Future of the Periodic Table
While the periodic table is currently considered complete with 118 elements, scientific curiosity and research continue. Scientists are still exploring the properties of superheavy elements and investigating the potential for even heavier elements beyond oganesson. Research at Berkeley Lab and other institutions focuses on precisely measuring the properties of these exotic elements, potentially challenging existing theories and opening new frontiers in physics and chemistry.
So, when asked “how many elements are on the periodic table,” the answer is currently 118. However, this number represents a snapshot in the ongoing story of scientific discovery. The periodic table is a testament to human curiosity and our relentless pursuit of understanding the fundamental building blocks of the universe, a pursuit in which Berkeley Lab has played, and continues to play, a leading role.
