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When Mendeleev's Periodic Table was devised, some elements hadn't been discovered yet. Therefore, there had to be gaps in it or the table would be rendered incorrect.
The rule of similarities states that the elements within a specific period/column are similar in a way and have the same number of electrons in the outer shell. E.g. Period 1 (alkali metals) react strongly with both air and water, have to be stored in oil, and are very alkali, hence the name.
Mendeleev used this rule to construct the periodic table. The amazing thing is, he guessed where elements were missing and left gaps. He even estimated their atomic masses!
In short, Mendeleev's periodic table had some bits missing. (e.g. technetium, discovered in 1936, a whole 65 years after Mendeleev's table was devised in 1871)
P.S. It's Mendeleev, not Mendeelev.
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How was mendeleevs periodic table like todays periodic table?
Mendeleev's periodic table arranged elements by increasing atomic mass and grouped elements with similar properties together. Today's periodic table is similar, but it is arranged by increasing atomic number, which reflects the number of protons in an atom's nucleus. Both tables also show periodic trends in properties as you move across and down the table.
What is the name of the table of elements?
It is named The PERIODIC TABLE. The periods being the horizontal rows The groups being the vertical columns.
Which element is the heaviest in periodic table?
who introduced the first Periodic Table
Which can be found on a periodic table elements compounds or mixtures?
Elements are found on periodic table. Compounds are not present on periodic table. The table does not contains mixture.Elements can be found on a periodic table. Compounds can be made by bonding two or more elements. But they are not depicted on the periodic table.
What is S4F3 on periodic table?
s on periodic table
How was mendeleevs periodic table like todays periodic table?
Mendeleev's periodic table arranged elements by increasing atomic mass and grouped elements with similar properties together. Today's periodic table is similar, but it is arranged by increasing atomic number, which reflects the number of protons in an atom's nucleus. Both tables also show periodic trends in properties as you move across and down the table.
How do the chemical symbols differ from chemical symbols found on the periodic table?
so that we can identifythem
What is the name of the table of elements?
It is named The PERIODIC TABLE. The periods being the horizontal rows The groups being the vertical columns.
How does the modern day periodic table of elements differ from Mendeleyevs chart?
The amount of elements included, and the fashion in which they are presented.
Do all elements of the periodic table have the same type of atoms?
No. Atoms differ in number of protons, neutrons and electrons.
What is a group in a periodic table.?
A group in Periodic Table is the column of element in periodic table
What is a chart that lists all the known elements?
It is called the Periodic Table of Elements.
How do groups and periods on the periodic table differ?
Groups are vertical and contain chemical elements with similar properties; periods are horizontal.
What are chemical compounds on the periodic table?
There are no compounds on the periodic table. The periodic table only lists elements.
Which element is the heaviest in periodic table?
who introduced the first Periodic Table
Does h stand for helium on the periodic table?
No, the symbol "H" stands for Hydrogen on the periodic table. The symbol "He" stands for Helium on the periodic table.
Which can be found on a periodic table elements compounds or mixtures?
Elements are found on periodic table. Compounds are not present on periodic table. The table does not contains mixture.Elements can be found on a periodic table. Compounds can be made by bonding two or more elements. But they are not depicted on the periodic table.
