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Simply for convenience. Were it included in the rest of the table those elements would fit between the transition ans alkaline-earth metals, and make the table too wide to be easily displayed on most pages.:-))))
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoLanthanide Series and Actinide Series
There are a couple reasons why the Lanthanide and Actinide Series are separated on the Periodic Table. One, they are put on the bottom of the periodic table mainly for aesthetic purposes (so the periodic table display isn't so wide).
Two, it also has to do with the electron configurations(how electrons are distributed among the orbitals of an atom) of the elements in both of these series.
In brief terms:
All of the elements in the Lanthanid series fill the 4f electron sublevel before the second 5d electron sublevel ever gets filled.
With the Actinide series elements, the 5f electron sublevel is filled before the 6d electron sublevel gets filled.
Hydrogen
Hydrogen is considered to be a unique element, as it only has 1 electron thus exhibiting some unique behavior. It can either gain an electron (alkali metal-like behavior) and gain an electron configuration identical to that of Helium or lose an electron and be just a lone proton (halogen-like behavior). It is often categorized as an alkali metal due to it having only 1 electron in its outermost shell (in this case, its only electron shell), although hydrogen is not actually a metal. It is being debated by some as to whether hydrogen should be classified as an alkali metal or as a halogen.
Wiki User
∙ 13y agoRare earth metals are an extremely reactive group on the periodic table. They are rare because they tend to react with everything, so are usually not found pure.
Wiki User
∙ 13y agobecause when it was made those metals were not discovered yet and they all fit in between two different elements
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What period on the periodic table of elements contains radioactive elements and what are they called?
it was found in 1896. you can not find them on the periodic table. you may find some, but often some are.
What is the similarities in the modern periodic table and Mendeleev's table?
They have simliar properties and same elements although later on more elements were added to the modern periodic table.=Both periodic tables have elements grouped by similar properties. Mendeleev's periodic table had elements arranged in order of increasing atomic mass in columns with similar properties. While many of the elements are in order of atomic mass on the modern periodic table, some are not, as the modern table has elements arranged in order of increasing atomic number.=
To what does the term periodic in periodic table refer?
Periodic means reoccuring. On the periodic table, periodic refers to the elements in each group having some of the same simularities and some of the same properties.
Which elements are in BaCI2?
it is some sort of Compound found in elements on the periodic table
What sentence can you make using the words periodic table and nucleus?
Some elements in the periodic table have a nucleus that is surrounded by a cloud of electrons with a negative charge. This is one sentence using nucleus and periodic table.
How many elements are you periodic table?
118 elements are in the periodic table of elements; some of them are still unnamed (January 2013).
What are some commonly used compounds on the periodic table?
the periodic table has no compounds it is a table of elements.
What are some examples of stable elements and where are they found in the periodic table?
noble elements are the stable elements. They are found in group 18 in the periodic table.
What period on the periodic table of elements contains radioactive elements and what are they called?
it was found in 1896. you can not find them on the periodic table. you may find some, but often some are.
Why do some elements get excluded from the periodic table?
No element is excluded from the table.
What are some sayings from the elements in periodic table?
I Am NeRdy
What are some ways that elements are arranged on the periodic table of elements?
Mendeleev arranged the elements in a table in the increasing order of atomic masses and repeating periodic properties. In the modern long-form of periodic table, the elements are arranged in the increasing order of atomic number and repeating periodic properties.
What is the similarities in the modern periodic table and Mendeleev's table?
They have simliar properties and same elements although later on more elements were added to the modern periodic table.=Both periodic tables have elements grouped by similar properties. Mendeleev's periodic table had elements arranged in order of increasing atomic mass in columns with similar properties. While many of the elements are in order of atomic mass on the modern periodic table, some are not, as the modern table has elements arranged in order of increasing atomic number.=
What is meant by the Periodic Table?
A table in which properties of elements are repeated after some interval.
What are some elements of periodic table that begin with the letter J?
No element in the periodic table begins with the letter J.
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.
To what does the term periodic in periodic table refer?
Periodic means reoccuring. On the periodic table, periodic refers to the elements in each group having some of the same simularities and some of the same properties.
