Table of Contents
The first stage of modern periodic table
The evolution of modern periodic table between the years 1789 – 1862 AD as follows:
In 1789, the French chemist “Antoine Lavoisier” made the first list of substances that could not be divided further, such as “magnesium oxide and barite”, but he excluded soda and potash, because he believed that they could be divided more.
In 1805 AD the periodic table appeared for the first time by the scientist “John Dalton“, who classified the elements based on atomic masses.
In 1807, the scientist “Humphry Davy” divided soda and potash, discovered the elements sodium and potassium, and noticed that these two elements were remarkably similar in their properties. At the same time, a group of scientists realized the similarities between the elements magnesium, calcium, barium and strontium.
In 1862, the French mineralogist Alexandre-Emile Bejoy developed a system for ordering all known elements based on their atomic mass. He placed the positions of sixty elements and arranged them according to their increasing atomic masses.
The second stage of modern periodic table
The periodic table evolved between the years 1869-1894 AD as follows:
In the science of 1869 AD, the Russian chemist “Dmitriy Mendeleev” developed a periodic table of the known elements, and arranged them periodically based on atomic weight. and placing elements with similar properties under each other, leaving blanks for elements that did not yet exist.
In the year 1894 AD, the scientist “William Ramsay” discovered the noble elements, and realized that they constituted a new group in the periodic table. It is worth noting that the discovery of these elements provided additional evidence for the accuracy of Mendeleev’s periodic table.
The third stage of periodic table
It is named after the modern periodic table
In 1913, British physicist Henry Moseley discovered during the process of analyzing the frequency of X-rays emitted from some elements that the basis of the arrangement of the elements is the atomic number and not the atomic mass.
The arrangement of elements with similar chemical properties in the columns is called “groups”, while the rows in the periodic table are called “cycles”.
Hence, we find that the modern periodic table has developed through a long history of attempts by chemists to arrange the elements according to their interaction and other properties as an aid in predicting chemical behavior.
By the 20th century it became clear that the periodic relationship in the periodic table is based on atomic numbers, rather than atomic masses. Since the modern periodic table arranges the elements in increasing order of their atomic numbers, groups of atoms with similar properties are in the same vertical column.
Each square represents an element and contains the atomic number, symbol, average atomic mass, and sometimes its name. The items are arranged in seven horizontal rows called cycles, and 18 vertical columns called groups. The groups are named at the top of each column, and the IUPAC recommends using numbers 1 through 18, because these designations are the most common.
A new look for modern periodic table
Scientists at Kyoto University in Japan presented a new formula for the shape of the periodic table, in contrast to Mendeleev’s table, which is based on electrons in an atom, and is based on the behavior of protons in the nucleus.
Chemistry Foundations reports that scientists have dubbed the new periodic table Nucletouch.
It is reported that in 1963 the Nobel Prize in Physics was awarded for the theory of the structure of the shell of the nucleus, according to which the shell of the nucleus of an atom consists of nickel shells filled with protons and neutrons, as in the structure of an atom that its shell is filled with electrons.
Mendeleev’s periodic table is considered one of the most important scientific achievements, and its famous form is based on the structure of the shell of electron orbitals in the atom.
But the atom consists of two types of charged particles, each of which defines an element, ”said Yoshitero Maino, one of the co-authors of each element. Electrons revolve around the nucleus in which the protons are located.”
“Practically in this system, everything is limited to the electrons in each atom. The atom is considered stable, when the electrons are complete in their orbits around the nucleus, as in the noble gases, where the number of electrons in their orbits is 2, 10, 18, 36 and so on.” They are called magic numbers. “
Based on this, the scientists decided to apply the same to protons that also have magic numbers -2, 8, 20, 28, etc., and put the elements with this magic number of protons in the middle of the new periodicity. Table – helium, oxygen, calcium.
Scientist Koichi Hageno says, “Like the electrons of the noble gases, the orbits of the nucleus are filled with protons, which ensures their stability. We in our nuclear periodic table also see that the nucleus, as a rule, is spherical in elements close to magic numbers, and is distorted in elements that move away from them” .
The researchers hope that their proposed alternative way of representing chemical elements will help scientists take a new look at the known laws of physics and chemistry, which will lead to new discoveries.