Origination
As the name suggests, the periodic table is a table full of elements structured in an orderly manner according to their atomic numbers, and other properties. While certain elements have achieved widespread recognition from an early stage to most people, the table serves as a comprehensive map of the building blocks of matter.
The first periodic table was created by a Russian chemist named Dmitri Mendeleev in 1869. It was later revised by Henry Moseley, which is known as the modern periodic table, in 1913.
The periodic table provides much information about classifying elements and organising them into various groups and sections. In addition to this, it also provides information about each element.
This version of the table is compiled by astronomer Jennifer Johnson from Ohio State University.
The provided table illustrates the comprehensive spectrum of the origins of elements within the periodic table, spanning from their inception during the Big Bang to the creation of elements through human intervention.
Big Bang Theory
The first two elements, both, in the periodic table and the universe, were helium and hydrogen. Their origin was the Big Bang itself. These elements were formed in the hot, dense conditions of the early universe, about 3 minutes after the Big Bang.
In three minutes, the universe's temperature rapidly cooled from 1³² Kelvin to approximately 1⁹ Kelvin. At this temperature, Big Bang nucleosynthesis, or the production of light elements, could take place.
Big Bang Nucleosynthesis is the process of forming Helium and Hydrogen after the Big Bang. It occurs when the universe expands and cools. The universe was extremely hot and dense during the first few minutes after the Big Bang, allowing protons and neutrons to combine and form hydrogen & helium nuclei. These are called ions.
Side Note:
There are three types of Nucleosynthesis: Big Bang Nucleosynthesis, Stellar Nucleosynthesis and Supernova Nucleosynthesis. Nucleosynthesis is essentially the process of the formation & evolution of the universe.
After further expansion of the universe, the nuclei of both hydrogen and helium could attract and hold on to electrons. The neutral atoms, as we know them today were eventually formed; this took place about 300,000 years after the Big Bang.
In addition to Hydrogen and Helium, traces of other elements were also present. These elements were mostly isotopes of Hydrogen and included Deuterium and Tritium. These isotopes are not complex structures and only require additional neutrons.
According to the Big Bang theory, most of the helium in the universe was created during the first few minutes after the Big Bang. However, stars also fuse elemental hydrogen into helium in their cores. These reactions account for 85% of the Sun’s energy.
Because of the difference between the formation of neutral elements and ions (the difference is between 3 minutes and 300,000 years), the matters have formed at very different times resulting in a key ratio: there was 75% hydrogen and 25% helium.
Different eras between the Big Bang and the formation of Hydrogen and Helium
Hadron & Lepton Era: Quarks begin forming new particles such as protons and neutrons. Although the quarks can form various types of Hadrons, very few can stay stable for a long time.
Nucleosynthesis Era: Now, the universe has cooled down, expanded to one hundred billion kilometres and one second has passed. It is now cold enough for all the neutrons to decay in protons to allow the formation of nuclei.
Opaque Era: Atoms were formed out of hadrons and electrons making the ion a stable atom.
From the table above, we can deduce that elements with an atomic number between 95 and 118 are human-made elements. Along with these elements, there are a few others which man also made.
These elements are known as synthetic elements, made from the use of cyclotrons. Synthetic elements are unstable and decay at varying rates. Their half-lives range from 15.6 million years to a few hundred microseconds. Once created, many of these elements quickly decay into simpler elements.
In laboratories, elements & isotopes are created by adding protons or neutrons to existing elements. This can be done by:
- Firing a beam of subatomic particles at an atom of radioactive element
- Colliding atoms with each other
- Smashing protons or neutrons into atoms
The process of changing one chemical element into another by altering the number of protons in the nucleus is called nuclear transmutation. This can be achieved through processes such as Nuclear fission, Nuclear fusion, and Particle bombardment.
For example, scientists discovered that by allowing fast neutrons to collide with the common isotope of uranium known as U-238 in a nuclear reactor, the “new” element plutonium was made.
An example of Nuclear Transmutation
Rutherford bombarded nitrogen atoms with high-speed alpha particles from a natural radioactive isotope of radium. The reaction resulted in protons: N147+He42⟶O178+H11
Human-made elements
The origins of elements beyond atomic number 95 up to 118 differ significantly from those formed during the Big Bang. These elements are synthetic or human-made because they do not occur naturally in the universe due to their extremely rapid decay rates.
Creating human-made elements is a fascinating and complex process that involves advanced technology and collaboration among scientists. Elements 95 through 118 are known as transuranium elements, and they are all synthetic. (meaning they do not occur naturally and must be created in a laboratory setting)
The process of creating human-made elements typically involves particle accelerators or nuclear reactors. Here’s a simplified overview of the steps involved:
Particle Accelerators: Particle accelerators, such as cyclotrons or linear accelerators, are used to accelerate charged particles, such as protons or heavier ions, to very high speeds. These accelerated particles are then collided with target atoms to induce nuclear reactions.
Nuclear Reactions: When accelerated particles collide with target atoms, they can induce nuclear reactions that lead to the formation of new, heavier elements. These reactions often involve the fusion of nuclei, where two lighter nuclei combine to form a heavier nucleus or the bombardment of a target nucleus with high-energy particles, causing it to undergo nuclear transmutation.
Isotope Separation: After a nuclear reaction occurs, it’s essential to separate the newly formed element from other reaction products and target materials. Isotope separation techniques, such as chromatography or electromagnetic separation, isolate the desired isotope of the newly created element.
Identification and Confirmation: Once the element has been isolated, scientists use various analytical techniques to confirm its existence and identify its properties. This may involve measuring its radioactive decay properties, studying its chemical behaviour, or conducting spectroscopic analysis.
There are several examples of human-made elements; a few such examples include:
- Plutonium (Pu, element 94): Plutonium was first synthesized in 1940 by a team led by Glenn T. Seaborg and Edwin McMillan at the University of California, Berkeley. It played a crucial role in the development of nuclear weapons during World War II and has various applications in nuclear reactors and weapons.
- Curium (Cm, element 96): Curium was first synthesized in 1944 by the same team that discovered plutonium, led by Glenn T. Seaborg. It’s named after Marie and Pierre Curie and has applications in research and as a heat source in some types of spacecraft.
- Lawrencium (Lr, element 103): Lawrencium was first synthesized in 1961 by a team of scientists led by Albert Ghiorso at the Lawrence Berkeley National Laboratory. Lawrence, the inventor of the cyclotron.
- Oganesson (Og, element 118): Oganesson is the heaviest element currently recognized on the periodic table. It was first synthesized in 2002 by a team of Russian and American scientists at the Joint Institute for Nuclear Research in Dubna, Russia, and the Lawrence Livermore National Laboratory in California, USA.
Because of the nuclear weight of these elements, and other characteristics of these elements, they tend to have nuclear instability. Although this is the case, they still exhibit periodic trends and have practical applications.
Further Explanation
Nuclear Stability: Human-made elements beyond uranium often have short half-lives due to their high levels of nuclear instability. This instability arises from the repulsive forces between protons in the nucleus, which increase as the atomic number increases. Consequently, many transuranium elements exist only fleetingly before decaying into lighter elements through radioactive decay.
Periodic Trends: Despite their synthetic nature, human-made elements still exhibit periodic trends in their properties, such as atomic radius, ionization energy, and electronegativity. These trends reflect the underlying structure of the periodic table and the organization of elements based on their electronic configurations.
Technological Applications: Many human-made elements have practical applications in various fields, including nuclear energy, medicine, and materials science. For example, curium and californium are used as neutron sources in neutron activation analysis and as power sources in spacecraft, while americium is used in smoke detectors.
Cosmic Ray Collisions
Cosmic ray collisions are energetic events occurring when high-speed particles from outer space, such as protons and atomic nuclei, crash into atoms within our atmosphere. These collisions unleash a cascade of reactions that lead to the formation of new atoms, including elements like beryllium and boron.
When a cosmic ray collides with an atom in the Earth’s atmosphere, it can knock off one or more of its electrons, resulting in an ionized atom. These highly charged ions then interact with nearby atoms, initiating a chain of reactions known as spallation. During spallation, the ionized atom fragments into smaller pieces, including nuclei of lighter elements like lithium, beryllium, and boron.
Beryllium and boron, specifically, are formed through successive collisions and rearrangements of particles.
Beryllium, with its four protons, is formed when lithium nuclei capture additional protons, gradually building up to the desired atomic structure.
Boron formation follows a similar process, where beryllium nuclei undergo further spallation events, incorporating more protons until they reach boron’s five-proton configuration.
These cosmic-ray-induced processes contribute significantly to the abundance of beryllium and boron on Earth and in the universe.
Dying Low Mass Stars
As stars approach the end of their lives, they become cosmic factories where new elements are born, shaping the diverse makeup of our universe. Even ordinary stars like our Sun play a crucial role in this grand cosmic dance.
During their early years, stars like the Sun burn hydrogen to create helium in their cores. But as they age and run out of hydrogen, they undergo dramatic changes. One of the most striking transformations occurs when they become red giants, expanding and shedding their outer layers into space.
In these expanding layers, conditions are just right for a different kind of nuclear fusion called the s-process. Here, atoms capture neutrons at a slow pace, gradually building up heavier elements.
Elements like carbon and nitrogen, essential for life as we know it, are primarily crafted during this process within the swirling layers of red giants. Helium atoms snatch up neutrons, transforming them into carbon, while further neutron captures lead to the creation of nitrogen.
But the cosmic party doesn’t stop there. The s-process also churns out a variety of other elements like cerium, barium, and titanium as neutrons interact with the star’s atomic building blocks.
Additionally, this process is responsible for the creation of elements like lithium and a range of others, including strontium, yttrium, zirconium, niobium, and molybdenum, through a series of nuclear interactions.
As these ageing stars near the end of their life cycles, they release their newly forged elements into space through stellar winds or in stunning displays like planetary nebulae or supernova remnants. This cosmic recycling ensures that the elements created within dying stars become the raw materials for new stars, planets, and, ultimately, the formation of life itself.
Dying High-mass stars
When we talk about the low-mass stars, a question about high-mass stars is bound to enter our minds. According to the American Museum of Natural History, “High-mass stars are very luminous and short-lived. They forge heavy elements in their cores, explode as supernovas, and expel these elements into space. Apart from hydrogen and helium, most of the elements in the universe, including those comprising Earth and everything on it, came from these stars.”
Iron, a fundamental element for life as we know it, is born in the heart of these stars through nuclear fusion. Helium atoms, under the intense pressure and heat within the star’s core, meld together to form the sturdy nuclei of iron.
In the cosmic ballet of stellar evolution, high-mass stars play a crucial role in creating elements heavier than iron. During a supernova explosion, a surge of free neutrons bombards nearby atoms, leading to the formation of elements like gold and uranium. This stellar alchemy enriches the universe, leaving behind a legacy that sparks wonder in humanity’s collective imagination.
(The Process Itself)
When high-mass stars reach the end of their lives, they undergo dramatic explosions known as supernovae. These cataclysmic events generate extreme temperatures and pressures, creating conditions necessary for the formation of elements heavier than iron.
During a supernova, the intense heat and pressure cause the star’s core to collapse rapidly. This collapse releases an enormous amount of energy, which triggers nuclear fusion reactions and generates a flood of free neutrons.
These free neutrons are crucial for the formation of heavier elements. As they collide with lighter nuclei in the star’s outer layers, they can be absorbed, leading to the rapid synthesis of heavier elements through processes like rapid neutron capture (r-process) and slow neutron capture (s-process).
Elements like gold, platinum, uranium, and many others are formed in this energetic environment as neutrons bombard and transform lighter nuclei into heavier ones. This process, occurring within the explosive aftermath of a dying high-mass star, enriches the universe with a diverse array of elements essential for the formation of planets, stars, and life itself.
Radioactive Decay
Radioactive decay is one of the simpler processes for the formation of elements. Elements form through radioactive decay when unstable atomic nuclei spontaneously break down, emitting radiation in the process. This decay transforms one element into another, often resulting in the creation of a different element with a different atomic number. For example, uranium-238 decays into thorium-234 through alpha decay, emitting an alpha particle consisting of two protons and two neutrons.
Another example is the decay of potassium-40 into argon-40 through beta decay, where a neutron in the potassium nucleus transforms into a proton, emitting an electron (beta particle) and an antineutrino. This process converts one potassium atom into an argon atom.
Radioactive decay plays a significant role in the formation of elements like lead from uranium and thorium decay chains, helium from the alpha decay of heavy elements, and argon from the decay of potassium-40. These processes contribute to the abundance and diversity of elements in the universe.
Merging Neutron Stars
When neutron stars merge, they overflow with energetic processes, culminating in the production of heavy elements through the r-process.
During the inspiral and subsequent collision of neutron stars, immense gravitational forces compress matter to densities exceeding nuclear saturation, creating conditions conducive to neutron-rich environments. As the neutron stars merge, a significant portion of their combined mass is ejected in the form of a neutron-rich material, commonly referred to as the “neutron-rich ejecta.”
Within this neutron-rich ejecta, rapid neutron capture occurs on timescales shorter than beta decay, facilitating the synthesis of heavy elements via neutron-rich isotopes. Neutrons are rapidly captured by seed nuclei, typically iron-group elements abundant in the ejecta, leading to the formation of neutron-rich isotopes of heavier elements.
The r-process proceeds through a series of neutron captures followed by beta decay, where unstable neutron-rich isotopes decay into more stable elements, emitting beta particles and antineutrinos in the process. This rapid neutron capture overwhelms the radioactive decay timescales, allowing for the efficient production of heavy elements.
Notably, gold (Au), platinum (Pt), uranium (U), and other heavy elements with atomic numbers exceeding iron (Z > 26) are predominantly synthesized through the r-process during neutron star mergers. For instance, the production of gold occurs through the rapid neutron capture and subsequent beta decay of isotopes such as platinum and mercury, ultimately leading to the formation of stable gold nuclei.
Furthermore, the intense environment of neutron star mergers facilitates the creation of rare isotopes and elements inaccessible through other nucleosynthesis pathways. Isotopic signatures and abundance patterns observed in astrophysical environments, such as the solar system’s isotopic composition, can be attributed to the unique nucleosynthesis conditions associated with neutron star mergers.
White Dwarf Supernovas
Type Ia supernovae, resulting from the explosive demise of white dwarf stars, represent pivotal events in astrophysics with profound implications for our understanding of nucleosynthesis and cosmic chemical evolution. These thermonuclear explosions, triggered by the accretion of material onto a white dwarf in a binary system, unleash an extraordinary burst of energy that reverberates throughout the cosmos.
The progenitor system of a Type Ia supernova typically consists of a white dwarf star, composed primarily of carbon and oxygen nuclei, in close orbit with a companion star, often a main-sequence star or another white dwarf. As the white dwarf accretes matter from its companion, the increasing gravitational pressure compresses the star’s core until it surpasses the Chandrasekhar limit, leading to catastrophic collapse.
The onset of collapse initiates a runaway fusion reaction within the white dwarf’s core, igniting a thermonuclear explosion that disrupts the star and ejects its outer layers into space at velocities approaching 10,000 kilometres per second. This explosive release of energy, equivalent to the luminosity of billions of stars, marks the birth of a Type Ia supernova.
Central to the nucleosynthesis process in Type Ia supernovae is the rapid fusion of carbon and oxygen nuclei in the white dwarf’s core, leading to the production of heavy elements. The fusion of carbon and oxygen into heavier nuclei, such as nickel-56 (Ni-56), serves as the primary energy source driving the explosive expansion of the supernova ejecta.
Nickel-56, synthesized during the initial stages of the supernova explosion, undergoes radioactive decay through beta decay processes, ultimately transforming into stable iron-56 (Fe-56). The decay of Ni-56 to Fe-56, accompanied by the emission of energetic electrons (beta particles) and neutrinos, contributes significantly to the luminosity and kinetic energy of the expanding supernova remnant.
Moreover, the extreme conditions within the expanding supernova ejecta facilitate the rapid capture of neutrons by existing atomic nuclei, leading to the synthesis of neutron-rich isotopes and heavy elements through the r-process. Elements such as strontium (Sr), barium (Ba), and lanthanides (e.g., cerium, neodymium) are among the multitude of heavy elements synthesized during the explosive nucleosynthesis of Type Ia supernovae.
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