HISTORY & EVOLUTION OF PERIODIC TABLE OF ELEMENTS
"Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Ne..." The periodic table can be said to be a god-level "Martial Arts Cheats" for chemical research and learning. It provides a good help for us to learn chemistry. Do you know it? What is the origin and evolution of?
In 1789, French chemist Lavoisier classified 33 elements known at the time in the "Compendium of Chemistry" and produced the first element classification table, which is divided into four categories: gas, metal, non-metal, and soil.
In the early nineteenth century, after British chemist Dalton proposed atom theory, chemists linked atom theory with the concept of elements, and established a more accurate element classification method by measuring the atomic weight of each element.
In 1829, the German chemist Debeleiner proposed the "three element group" theory. He believed that there must be a certain regularity between the atomic weight of an element and the chemical properties of the element.
In 1862, French geologist Jean Gudeau proposed a classification method called "Spiral Diagram".
In 1865, the British chemist Newlands independently proposed the "octave" classification. He arranged the atomic weights of the 62 elements known at that time in increasing order and found that the properties of the elements have periodic repetitions, with every eight elements as a cycle.
In 1869, Russian chemist Mendeleev produced a periodic table, which is the most important research result in the history of chemical research. It is said that on one night of that year, Mendeleev dreamed that 63 known chemical elements fell in the grid one by one, forming a row upon row of tables. When he woke up from a dream, he immediately restored the table in the dream and made the first periodic table of elements. Of course, this is a legend. The fact is that he was inspired by the popular card game at the time based on the continuous research and discovery of various chemical elements by many scientists before. He wrote the elements on the cards and combined them according to chemical and physical properties. They are arranged. In the end, a periodic table in which the chemical properties of the elements in each column are similar, and the reaction law of the elements in each column is gradually changing from left to right.
On the other hand, Mendeleev presciently left blanks when drawing the periodic table of chemical elements. He realized that certain elements were missing, and accurately predicted the nature of the missing elements. Over time, the 11 elements he predicted were found one by one.
So far, chemists have discovered 118 elements. Element 118 is not the end of the periodic table. The creation of element 119 will usher in a new era, and it will also be a new era in the periodic table.
The periodic table of chemical elements has opened a door for us to study chemistry. How close is chemistry to us?
Everything we hear, see, smell, taste, and touch is related to chemical substances. For example, a seemingly ordinary glass of water is actually composed of hydrogen and oxygen, as well as some other mineral elements, such as sodium, calcium, magnesium, chlorine, etc.; an ordinary grass is actually rich in potassium , Sodium, magnesium and other elements. In addition, petroleum can be transformed into fuel after chemical transformation, and become things we come into contact with every day (such as lipsticks, medicines, clothes, etc.), and all products related to plastics and organic materials have their predecessors black and sticky. Of oil.
Although most people can't memorize the periodic table of elements, every bit of people's lives are permeated with chemistry, and chemistry research has also played a key role in the advancement of social science and technology.
Does the periodic table contain all elements?
All substances in the world are composed of various elements, and there are a total of 118 elements that have been confirmed in the world today, and they are perfectly arranged on the periodic table, 7 rows of 118.
There are many kinds of elements in the world, which seem chaotic on the surface, but in fact there are traces to follow. Early on, people discovered that the most important difference between different elements is the number of protons in the nucleus, such as hydrogen. There is only one proton in the nucleus of an atom, and there are two protons in the nucleus of a helium atom. So, according to this law, people began to sort the elements, and the periodic table of elements was born.
Hydrogen with one proton in the nucleus is element one, helium with two protons is element two, and lithium with three protons is naturally element three, and the number of protons contained in the atom becomes their serial number. So orderly. Of course, what is reflected in the periodic table is not just the order of the number of protons.
When Mendeleev wrote the periodic table of elements, in addition to considering the atomic number, he also divided it into seven main groups and seven subgroups according to the nature of the elements, and divided it into seven periods according to the maturity of electrons. Therefore, The periodic table we see is seven rows.
Is Element 119 possible?
The current periodic table looks very perfect, because there are 118 elements in total, and the 118th element is just at the end of the seventh row. The entire periodic table looks very neat, so does the type of element arrive? The limit is over. Is it possible to discover new elements in the future? In fact, the term "discovery" here is not particularly accurate. To be precise, it should be manufacturing. The 118 elements that have been identified are not all from nature. Many of them are man-made elements. Specifically, starting from element 95, it can only be manufactured artificially. Before element 95, some were artificially synthesized. Manufactured, so out of 118 elements, 92 are found in nature, and 26 are synthetic elements.
How do humans make new elements? Simply put, it is "acceleration" and "bombardment".
Scientists use the Large Hadron Collider to accelerate the atoms of one substance, and then use it to bombard another substance, so that the two substances merge to form a new substance. The first synthetic element obtained by mankind was element 43 T. At that time, mankind discovered element 42 molybdenum and element 44 ruthenium successively in nature. According to the periodic table, it is obviously between elements 42 and 44. There is still an undiscovered element 43.
Since element 43 has not been discovered in nature for a long time, in 1937, physicist Ernest Lawrence used a cyclotron to accelerate deuterium containing a proton, and bombard element 42 with the accelerated deuterium nucleus. Molybdenum, and the two blended together, and the 43 proton element Tung was born.
In this way, in the following seventy years, humans successively obtained 26 artificial synthetic elements using this method, and the last one synthesized was element 118, Og.
The reason why the symbol is used here is because its name cannot be typed out, because its Chinese name should be "qi" followed by "奥". I have not found an input method that can type this word. Obviously I am not the one in this predicament, so in some places it will be written directly as "Qiao". Element 118 is obtained by bombarding element 98 with element 20 calcium, and the sum of the two is exactly 118.
However, the larger the number of the atom, the more unstable it is. Although we can synthesize element 118 artificially, it can only exist for one ten-thousandth of a second, and it will decay into element 116, and then it will continue to decay. So in history, humans have only synthesized three 118 atoms.
The first synthesis of element 118 was in 2003, and it was officially confirmed as element 118 in 2016. After so many years, although no new elements have been confirmed to be synthesized, this does not mean that the periodic table It came to an end.
In fact, many countries are researching and manufacturing new elements. Russian scientists even claimed that they had synthesized element No. 119 that exploded in water, but this has not been confirmed. In fact, element 119 is very much anticipated, because now element 118 is at the end of the seventh row, and the periodic table is perfect and tidy, and once element 119 appears, this visual perfection is Will be broken, it will become the first element in the 8th row, which will open up more possibilities. Now it is difficult for us to make a conclusion, whether the periodic table of the elements can be extended indefinitely, or there is an unknown end, but we know that, at least for now, it is not over yet.