0
Mendeleev discovered the Periodic Law and produced his first Periodic Tables when about 65 elements were known, about 5 of which were poorly identified and later proved to be mixtures of similar elements. New elements were, at that time, being discovered at the rate of about one element per two years.
Today, we know exactly how many elements there are, except that it is not totally clear how many artificial heavy elements it will be possible to prepare and characterize. We know 80 stable elements, another dozen or so that are radioactive and unstable, but can be found in nature, and another 20 or more that have been produced artificially. Some are long lived and can be prepared in large quantities and can be useful --e.g. plutonium and americium. Some others have only been prepared in quantities of a few atoms, and identified by a characteristic radiation signal on their decay.
So the rough answer is about 30 elements have been discovered since 1871, and about another 22 have been artificially prepared.
What else can I help you with?
How many blank spaces were in mendeleeves periodic table?
There were 3 blank spaces in mendeleev's Periodic Table. He left it for the elements which were not discovered at that time.
What do the long dashes represent on mendeleev's periodic table?
The long dashes on Mendeleev's periodic table represent gaps where elements had not yet been discovered but were predicted to exist based on the periodic pattern of elements. Mendeleev used these gaps to accurately predict the properties of the missing elements, leading to the discovery of new elements.
What is the greatest triumph about mendeleev's periodic table?
Dmitri Mendeleev's greatest triumph with the periodic table was his ability to predict the properties of undiscovered elements. Gaps in the table led him to propose the existence of new elements with specific characteristics, which were later discovered and matched his predictions, confirming the validity of his periodic law.
Is mendeleev invented periodic table?
Yes, Dmitry Mendeleev is credited with creating the periodic table in 1869. He arranged the elements based on their properties and predicted the existence of some elements that were discovered later. His work laid the foundation for the modern periodic table.
How many blank spaces did Mendeleev leave in the periodic table which represented elements that had not yet been discovered?
Mendeleev left gaps for eight elements in his periodic table that were yet to be discovered. These gaps eventually corresponded to the elements gallium, germanium, scandium, technetium, francium, and technetium.
How many blank spaces were in mendeleeves periodic table?
There were 3 blank spaces in mendeleev's Periodic Table. He left it for the elements which were not discovered at that time.
Who discovered a pattern to the elements of the periodic table in 1869?
Demitri Mendeleev discovered a pattern to the periodic table in 1869.
Who discovered the symbols in the periodic table of elements?
Dmitri Mendeleev
Was Mendeleev's periodic table accurate enough that he was able to use it to predict the existence and several properties of certain elements that had not yet been discovered?
Mendeleev was able to predict the properties of the elements that were not discovered at that time. He left gaps for these elements in his Periodic Table.
What do the long dashes represent on mendeleev's periodic table?
The long dashes on Mendeleev's periodic table represent gaps where elements had not yet been discovered but were predicted to exist based on the periodic pattern of elements. Mendeleev used these gaps to accurately predict the properties of the missing elements, leading to the discovery of new elements.
What did Dimtri Mendeleev did not know about the periodic table?
Only some elements were discovered during the life of Mendeleev.
What did Dimitri Mendeleev discovered?
He discovered the elements and and weighed them and latter placed the elements in order to form the periodic table.
Who wrote or found the periodic table of elements?
The periodic table of elements was created by Dmitri Mendeleev, a Russian chemist, in 1869. He arranged the elements based on their atomic mass and properties, and left gaps for elements that were yet to be discovered. Over time, new elements were discovered and added to the periodic table by various scientists.
Who was the father of the periodic table?
Father as in who created it? That would be Mendeleev, he even named the 101st element after himself. Improving: Mendeleev, was the father of the periodic table of elements, he discovered this method of organizinging the elements by playing a game of solitare with the chemical symbols.
Who discover the old Periodic Table?
Mendeleev discovered old periodic table. He arranged elements in order of atomic masses.
The usefulness of Mendeleev's periodic table was comfirmed by?
Mendeleev's periodic table was confirmed to be useful because it accurately predicted the properties of elements that had not been discovered at the time. When new elements were discovered and found to fit into the gaps Mendeleev had left, it provided strong evidence for the effectiveness of his periodic table in organizing elements based on their properties. This confirmed the periodicity of elements and highlighted the power of the periodic table as a tool for understanding and predicting the behavior of elements.
How did mendeleev organize the periodic table?
He is credited as being the creator of the first version of the periodic table of elements. Using the table, he predicted the properties of elements yet to be discovered.
