How many chemical elements are there?
The chemical element is a type of atom such as hydrogen or oxygen. Since 2011, 118 elements have been observed, with 98 of them naturally on Earth. 20 elements are artificially created in nuclear reactors or experiments with particle accelerators. The first synthetic element to be created in considerable quantities was plutonium, element 94. Plutonium is also the most difficult atom naturally found on Earth. With a half -life of only 80 million years, plutonium occurs in extremely small quantities in uranium ores. Current chemical elements come from one of three sources: supernova nucleosynthesis, star nucleosynthesis and nucleosynthesis of the Big Bang. Nucleosynthesis occurs when the atomic cores are compressed so closely and at such a high heat that they overcome the mutual repel of their electron shells and produce heavier cores. In this way, hydrogen cores can be fused into the Helium core, which in turn can connect to the carbon core if the conditions sufficiently temperament reachENO pressure.
In the beginning, the universe was so hot and dense that it folded out of anything other than free quarks - protons and neutrons components - electrons and radiation. For millions of seconds, Quarks began to join the barryons: protons and neutrons. The first twenty minutes after the Big Bang the temperature of the universe exceeded the temperature in the center of the brightest stars, with a density greater than the air. During this period, protons and neutrons collided vigorously to create larger cores: deuterium and two helium isotopes. 25 percent All things in the universe were converted into helium, with about 75 percent of hydrogen, along with trace many heavier elements such as lithium. It is a similar ratio of the current day of chemical elements.
The first stars created about 300 million years after the big bang, vitipulation other forms of nucleosynthesis called star nucleosynthesis. In a star nucleosynthesis, it is subject to a very compacted matter in the center of a nuclear starFusion, releases a large amount of energy and compensates for gravitational forces to collapse the star. This can be considered a continuously exploding h-bomb. The elements up to iron on the periodic table are formed in a star nucleosynthesis.
To create an element that is heavier than iron, a different type of nucleosythes, nucleosynthesis of supernova requires a different type of nucleosythes. Supernovs occur when the stars disastrously collapse after consuming all their nuclear fuel in their cores. The atmospheric envelope of the star collapses inward due to gravity, jumping from a core made of an almost im notable "electron degenerate" matter. During this sudden reflection, several percent of the star material is connected to heavier elements almost immediately. This releases enough energy for supernova to overshadow his host galaxy for days or weeks. During this incredibly energy cosmic event, elements are heavier than iron.