Chemistry 4th period
A chemical element is a uncorrupted chemical substance containing of one type of atom well-known by its atomic number, which is the number of protons in its nucleus. Elements are divided into metals, metalloids, and non-metals.
In chemistry, a artificial element is a chemical element that does not happen naturally on planet Earth, and therefore only be created artificially. As of the year 2012, we have only created exactly 20 artificial elements, these are those with the atomic numbers of 99-118. With a life ranging from as much of one year up to a few milliseconds all artificial elements are unstable.
Nine other elements were first created artificially and later considered synthetic, but later, these nine elements were discovered to exist naturally in trace amounts. For example, plutonium was first manufactured in the year 1940. One of the best known artificial elements is laypeople. It is so known because if its use in atomic bombs and other nuclear reactors.
The following elements do not occur naturally on Earth. All are transuranium elements and have atomic numbers of 99 and higher. Their position on the periodic table is also shown below.
1966 (USSR), 1969 (USA) *
1968 (USSR), 1970 (USA) *
There are a few ways in which synthetic elements can be...