Question

Besides gallium which other other elements have since been discovered that were left by mendeleev in his periodic table

Answer 1

In his periodic table, Mendeleev arranged the elements by atomic weight (relative atomic mass) Nowadays, we arrange the elements according to atomic number, but that information was not available in 1869. 1869 was the year that Russian chemist Dmitri Mendeleev (1834- 1907) published his Periodic "System" of the elements. Acc ording to the .org website www.rsc.org/education/ Other people, like Londoner John Newlands, Frenchman Alexandre Béguyer de Chancourtois, and German JuliusLothar Meyer made important contributions to the first Periodic Table but the main credit goes to Mendeleev." Here's a picture of a shaggy Mendeleev looking like a mad scientistlist the elements left to right in rows according to mass, and also from top to bottom in columns according to their properties. Mendeleev wasn't deterred by the poor quality of the data at that time. . Only about 50 elements were known In some cases, their relative atomic masses were miscalculated There were gaps where some elements were missing- not yet discovered . The atomic mass isn't a gooelements to get out of place But Mendeleev was convinced that listing the elements according to their properties in columns would create a "double entry" table with their atomic masses going across in rowS. Therefore, when the use of atomic mass instead of atomic number incorrectly located odine before tellurium, he knew enough to switch them anyway because of the properties of iodine. Another mathematical difficulty placed beryllium between carbon and nitrogen, wherethere was no space for it. Mendeleev simply changed the math in order to get beryllium into its correct slot in the periodic table. Most important was Mendeleev's predictions of elements as yet unknown. There were gaps in the table he created, but not only did he correctly predict that elements would be discovered that filled those gaps, he also predicted their properties. Three such predictions were proved correct in Mendeleev's lifetime, and two other elements that he predicted were foundHere is a color-coded periodic table that is useful and also quite beautifu.

Answer 2

Answer:

In his periodic table, Mendeleev arranged the elements by atomic weight (relative atomic mass) Nowadays, we arrange the elements according to atomic number, but that information was not available in 1869. 1869 was the year that Russian chemist Dmitri Mendeleev (1834- 1907) published his Periodic "System" of the elements. According to the  like Londoner John New land's, Frenchman Alexander Buyer de Courtesans, and German Lothario Meyer made important contributions to the first Periodic Table but the main credit goes to Mendeleev." Here's a picture of a shaggy Mendeleev looking like a mad scientist list the elements left to right in rows according to mass, and also from top to bottom in columns according to their properties. Mendeleev wasn't deterred by the poor quality of the data at that time. . Only about 50 elements were known In some cases, their relative atomic masses were miscalculated There were gaps where some elements were missing- not yet discovered . The atomic mass isn't a goo elements to get out of place But Mendeleev was convinced that listing the elements according to their properties in columns would create a "double entry" table with their atomic masses going across in rows. Therefore, when the use of atomic mass instead of atomic number incorrectly located iodine before tellurium, he knew enough to switch them anyway because of the properties of iodine. Another mathematical difficulty placed beryllium between carbon and nitrogen, where there was no space for it. Mendeleev simply changed the math in order to get beryllium into its correct slot in the periodic table. Most important was Mendeleev's predictions of elements as yet unknown. There were gaps in the table he created, but not only did he correctly predict that elements would be discovered that filled those gaps, he also predicted their properties.