/kloc-in the middle of 0/9th century, Russian chemist Mendeleev formulated the periodic table of chemical elements.
Mendeleev was born in 1834. Shortly after his birth, his father went out for medical treatment because he was blind, and he lost a teacher position that could support his family. When Mendeleev 14 years old, his father died, and then the fire swallowed up all the property in the family. It never rains but it pours. 1850, Mendeleev, whose family was in difficulties, started his college life with a meager grant, and later became a professor at Petersburg University.
Fortunately, Mendeleev lived in an extraordinary period when the chemical community explored the laws of elements. At that time, chemists all over the world were exploring the internal relations of dozens of known elements.
1865, British chemist Newlands arranged the elements known at that time in order of atomic weight, and found that no matter what kind of elements were counted, every eighth element was similar to the first one. This is very similar to the octave period in music, so he simply called this periodicity of elements "octave" and drew a table of "octave" to show the relationship between elements.
Obviously, Newlands has subconsciously touched the skirt horn of "Goddess of Truth" and almost revealed the periodic law of elements. However, conditions limited his further exploration, because there was an error in the measured value of atomic weight at that time, and he did not consider the undiscovered elements, but arranged them mechanically according to the atomic weight at that time, so he failed to reveal the internal laws between elements.
It can be seen that the discovery of any scientific truth will not be smooth sailing, and it will encounter resistance, some of which is even artificial. At that time, Newlands's octave was ridiculed by the British Chemical Society. The host asked sarcastically, "Why not arrange the elements in alphabetical order?"
Mendeleev didn't care so much. He devoted himself to hard exploration with amazing insight. It was not until 1869 that he recorded the main properties and atomic weights of the elements known at that time on a small card and collated and compared them repeatedly. Finally, he discovered the periodic law of elements and made the periodic table of elements accordingly.
Memorize the periodic table of elements first, and then you will gradually discover the laws of the elements of all ethnic groups. As long as the elements that have not been learned in the future belong to the same family, they all know what characteristics and chemical properties they have, so they cannot be extrapolated.
Horizontally, it is called period, which refers to the periodic cycle of the outermost electrons in a row of elements in the periodic table from 1 to 8.
Longitudinal family refers to a longitudinal element with the same number of electrons in the outermost layer, so its chemical properties are similar.
Maybe it's too colloquial ... explain it again for chemistry majors ~
I have studied information for 4 years and have never seen chemistry.
Only the outermost electrons of the main group elements are not completely discharged, but the secondary group has energy level transition, and the secondary outer electrons are not completely discharged. Go find a chemistry textbook for senior one.
It is better to use homophonic fantasy to remember: light (hydrogen) (helium) leaves (lithium) skin (beryllium), friends (boron) sigh (carbon) light (nitrogen) nourishes (oxygen), Buddha (fluorine) milk (neon) that (sodium) does not (magnesium), and repeatedly (aluminum) returns (magnesium).
It means: the frivolous child is raw, and friends lament that you have to raise him extensively. Our family's galeries lafayette, the child's grandmother said: that is impossible to raise. I went back to my hometown for remedies many times and left the money to others when I left. People have repeatedly said that you should give calcium to his teeth.
I made this up when I was in middle school chemistry. You see, it's been 20 years, and I still remember it clearly. Periodic table of elements ". This table reveals the secrets of the material world, unifying some seemingly unrelated elements to form a complete natural system. Its invention is a pioneering work in the history of modern chemistry, which has greatly promoted the development of chemistry. When people see this watch, they will think of its earliest inventor, Mendeleev.
Dmitri Ivanovich Mendeleev was born in Polsk, Siberia, Russia on February 7, 1984. This era is a period of rapid development of European capitalism. The rapid development of production constantly puts forward new requirements for science and technology. Chemistry, like other sciences, has made amazing progress. Mendeleev was born in this era. Mendeleev loved labor and study since he was a child. He believes that only labor can make people get a happy life; People can only become smart by studying.
When Mendeleev was at school, a famous chemistry teacher often gave them lectures. Enthusiastically introduce them to the new atomism initiated by British scientist Dalton at that time. Due to the advent of Dalton's new origin theory, the development speed of chemistry has been promoted and new elements have been discovered one by one. The science of chemistry excites people's hearts. The teacher's teaching broadened Mendeleev's thoughts and made him determined to devote his life to chemistry.
Mendeleev showed the superhuman spirit of perseverance and forgetting me during his college study. Illness tormented Mendeleev, and he became thinner and paler day by day due to countless blood losses. However, he always has a chemistry textbook in his anemic hand. There are many unclear questions in it, which linger in his mind and seem to call him to explore quickly. He climbed the road of science at the cost of his life. He said that I did this "not for my own glory, but for the glory of the Russian name." -After a while, Mendeleev didn't die, but got better day by day. Finally, I realized that the doctor's diagnosis was wrong, and all he got was tracheal bleeding.
Because Mendeleev studied hard, he did some creative research during his study, and he graduated from the university with excellent results in 1855. After graduation, he went to Simferopol and Odessa as middle school teachers. During this period, while teaching, he conducted research under extremely simple conditions and wrote a paper on specific volume. The natural grouping method of compounds according to specific volume is pointed out. 1857 1 month was approved as an associate professor in the chemistry teaching and research department of Petersburg university at the age of 23.
The road to climb the peak of science is difficult and tortuous. Mendeleev also suffered a lot on this road. When he became an associate professor of chemistry, he was responsible for teaching the course "Fundamentals of Chemistry". How many elements are there in nature in theoretical chemistry? What are the similarities and differences between elements, and what are their internal relations? How should new elements be discovered? These problems were in the exploratory stage in the field of chemistry at that time. In the past 50 years, chemists all over the world have made tenacious efforts to open this secret door. Although some chemists, such as Debelina and Newlands, objectively described some relationships between elements from a certain depth and different angles, they failed to find the correct classification principle of elements because they did not summarize all elements as a whole. Mendeleev, a young scholar, also rushed into this field without fear and began a difficult exploration.
He studied day and night, exploring the chemical characteristics of elements and their general atomic characteristics, and then recorded each element on a small paper card. He tried to capture the * * * identity in all the complex characteristics of elements. But his research failed again and again. But he didn't give in, didn't lose heart, and went on working.
In order to solve this problem completely, he went out of the laboratory and began to investigate and collect information abroad. 1859, he went to Heidelberg, Germany for further scientific study. In the past two years, he devoted himself to studying physical chemistry, which made him more solid in exploring the internal relations between elements. 1862, he inspected Baku oil field, made an in-depth study of liquids, re-measured the atomic weights of some elements, and gained a deep understanding of the characteristics of elements. 1867, he took the opportunity of working in the Russian exhibition hall of the World Industrial Fair held in France, and visited many chemical plants and laboratories in France, Germany and Belgium, which broadened his horizons and enriched his knowledge. These practical activities not only increased his ability to understand nature, but also laid a solid foundation for him to discover the periodic law of elements.
Mendeleev returned to the laboratory and continued to study his paper card. He arranged the elements with re-determined atomic weights in order of their atomic weights. He found that elements with similar properties have different atomic weights; On the contrary, some elements with different properties have similar atomic weights. He firmly grasped the relationship between the atomic weight and properties of elements, and constantly studied them. His brain is often dizzy from excessive tension. However, his efforts were not in vain. 1February 869 19, he finally discovered the quality law. His periodic law shows that the properties of simple objects, as well as the forms and properties of elemental compounds, are periodically dependent on the atomic weight of elements. Mendeleev boldly pointed out that some recognized atomic weights at that time were inaccurate in the process of sorting out the element list. For example, the atomic weight of gold recognized at that time was 169.2. Accordingly, gold should be ranked before osmium, iridium and platinum in the element list, because their recognized atomic weights are 198.6, 6.7 and 196.7 respectively, and Mendeleev firmly believes that gold should be ranked after these three elements. The retest results show that osmium is 190.9, iridium is 193. 1, platinum is 195.2, and gold is 197.2. Practice has proved the correctness of Mendeleev's assertion and periodic law.
There are still many gaps in Mendeleev's periodic table, which should be filled by undiscovered elements. Mendeleev theoretically calculated the most important properties of these undiscovered elements and concluded that they were between the properties of adjacent elements. For example, in the two spaces between zinc and arsenic, he predicted that the properties of these two unknown elements are like aluminum and like silicon. Just four years after his prediction, French chemist Boublanc discovered gallium from wurtzite by spectral analysis. Experiments show that the properties of gallium are very similar to that of aluminum, which is exactly what Mendeleev predicted. The discovery of gallium is of great significance, which fully shows that the periodic law of elements is an objective law of nature. It provides rules for studying elements, exploring new elements and looking for new materials in the future. The periodic law of elements exploded in the world like a heavy artillery!
Mendeleev discovered the periodic law of elements, which left immortal glory in the world and was highly praised by people. Engels once pointed out in his book Dialectics of Nature. "Mendeleev unconsciously applied Hegel's quantity to the qualitative law and completed a scientific feat, which can be on a horizontal line with Le Verrier's feat of calculating the orbit of the unknown planet Neptune."
Due to the limitation of the times, Mendeleev's periodic law of elements is not complete. The discovery of inert gas atmosphere in 1894 is a test and supplement to the periodic law. 19 13 years, after studying the relationship between the wavelength of roentgen rays and the atomic numbers of various elements, the British physicist Moselle confirmed that the atomic number is equal to the positive charge carried by the nucleus in number, and then made it clear that the basis of the periodic law is not the atomic weight, but the atomic number. The primary structure theory under the guidance of the periodic law not only gives a new explanation to the periodic law of elements, but also further clarifies the essence of the periodic law, making the natural law of the periodic law based on a stricter and more scientific basis. With the continuous improvement and development of later generations, the periodic law of elements plays an increasingly important role in people's struggle to understand, transform and conquer nature.
In addition to completing the feats of periodic law, Mendeleev also studied gas law, meteorology, petroleum industry, agricultural chemistry, smokeless gunpowder, weights and measures and so on. Because he always works hard day and night, he has achieved different degrees in these fields he studied.
1February 2, 907, the world-famous scientist died of myocardial infarction. But the precious property he left to the world will remain in the history of mankind forever.
The discovery of the periodic law of elements is the result of the joint efforts of many scientists.
1789, lavoisier published the first Zhang Yuansu table in human history in the Outline of Chemistry. In this table, he divided 33 known elements into four categories.
1829, D 'Urbervilles put forward the rule of three-element group after systematically analyzing 54 known elements at that time. He found several groups of elements, each of which has three elements with similar chemical properties. Moreover, in each group, the atomic weight of the intermediate element is similar to the average atomic weight of the elements at both ends.
1850, the German Peyton Coffer announced that there are not necessarily only three elements with similar properties; The difference between atomic weights of elements with similar properties is often 8 or a multiple of 8.
1862, the French chemist Jean-Claude Jean-Claude Jean-Claude Jean-Claude Jean-Claude Jean-Claude Jean-Claude Jean-Claude Jean-Claude Jean created a spiral diagram, creatively marking 62 elements at that time on a one-liter spiral around a cylinder in the order of atomic weight. He happened to find that elements with similar chemical properties all appeared on the same bus.
1863, British chemist Aldrin published the atomic weight and element symbol list, which listed 49 elements, leaving 9 spaces.
The above scientists and their research can only be said to be preliminary preparations to a certain extent, but these preparations are indispensable. Russian chemist Mendeleev, German chemist Meyer and British chemist Newlands played a decisive role in the discovery of the periodic law of elements.
During 1865, Newlands was studying the classification of chemical elements independently, during which he found a very interesting phenomenon. When the elements are arranged in the order of increasing atomic weight, the physical and chemical properties of the elements will be repeated every eight elements. From this, he arranged various elements in the order of increasing atomic weight, forming a cycle of several family systems. Newlands called this law "octave". The discovery of this correct law was not accepted by the scientific community at that time, but its discoverer, Newlands, was criticized and insulted. It was not until later that everyone believed in Menzier's elemental cycle that they became alert, and the Royal Society corrected the unfair attitude towards Newlands in the past. Mendeleev is the mainstay of discovering periodic elements. Inevitably, he also accepted incomprehension and pressure from all sides, including his own teacher, in his research work.
Mendeleev was born in 1834 and lived in Siberia before 10. Under the guidance of a political exile, he studied scientific knowledge and was very interested in it. 1847, Mendeleev, who lost his father, came to Petersburg with his mother. 65438-0850 entered the Central Normal University, worked as a middle school teacher after graduation, and later served as an associate professor at Petersburg University.
From 65438 to 0867, Professor Mendeleev was compiling a general chemistry textbook, Principles of Chemistry, in order to systematically teach inorganic chemistry. In the process of writing a book, he encountered a difficult problem, that is, how to organize the 63 elements known at that time in a logical way.
Mendeleev carefully studied the physical and chemical properties of 63 elements. After several unsatisfactory beginnings, he came up with a good way to systematically classify the elements. Mendeleev prepared many cards similar to playing cards, on which were written the names of 63 chemical elements and their atomic weights, oxides, physical properties and chemical properties. Mendeleev put these cards together in different ways and used them in the experiment of element classification. At first, he tried to divide the elements into three groups like D 'Urberville, but the result was not satisfactory. He separated nonmetallic elements and metallic elements into two rows, but failed. He fiddled with these cards in various ways, but failed to reach the best classification.
March 1869, 1, Mendeleev is still thinking hard about these cards. He first put the common elements together in the order of increasing atomic weight, then the uncommon elements, and finally only the rare earth elements were not all "seated", and Mendeleev reluctantly put them aside. After reading the discharged "card array" from beginning to end, Mendeleev was surprised to find that all known elements had been arranged in the order of increasing atomic weight, and similar elements appeared at certain intervals.
The next day, Mendeleev tabulated the results, which was the first periodic table of chemical elements in human history. In this table, the cycle is vertical and the family is horizontal. In Mendeleev's periodic table, he boldly reserved a place for the elements to be discovered, and pointed out in his paper on the discovery of the periodic table that if the elements are arranged in the order of atomic weight from small to large, new elements will be discovered where the atomic weight jumps too much, so the periodic law can predict the elements to be discovered.
In fact, the German chemist Meyer invented the "six-element table" as early as 1864, and this table already has the periodic table of chemical elements. A few months ago, Meyer simplified the "six-element table" and put forward the famous "atomic volume periodic table". This diagram is more quantitative than Mencken's first list of chemical elements, so it is more accurate. But Meyer failed to explain the chart systematically, and the chart focused on the embodiment of the physical properties of chemical elements.
187 1 65438+February, Mendeleev added the first periodic table and published the second table. In this table, the vertical row is changed to horizontal row, and a family of elements are used in the same vertical row, which highlights the periodicity of element attributes. At this point, the discovery of the periodic law of chemical elements has been successfully completed.
Objectively speaking, Meyer and Mendeleev discovered the periodic law of elements independently, but because Mendeleev studied the periodic law of elements most thoroughly, it is usually called Mendeleev's periodic law in the field of chemistry.