So people know!
No, columns of elements in the periodic table are called groups or families. Periods are the rows of elements that run horizontally across the table. Each period corresponds to the number of electron shells an element's atoms have.
The first periodic table was a handwritten table by Mendeleev. It had groups horizontally across the top and periods down the left hand side. The elements were all put into certain groups with only their chemicals symbols and atomic numbers depicted.
no its false i put true and it was wrong they are called groups!!!!!
Oh honey, those two rows at the bottom of the periodic table are like the misfits at the cool kids' table. They're separated because they're the f-block elements, also known as the lanthanides and actinides. They're down there minding their own business, doing their own thing, and adding a little extra spice to the periodic table.
1869 by Mendeleev
I am assuming you mean to ask why elements go into specific groups Elements that have the same number of valence electrons are put into the same group. Because they all have the same number of valence electrons, it could also be said that elements are put into groups based on their chemical properties.
Mendeleev organized elements by their atomic mass and properties, arranging them in a table where elements with similar properties were grouped together. Gaps were left for undiscovered elements, allowing Mendeleev to predict the properties of these missing elements based on their position in the table. This led to the development of the first periodic table.
Atomic Number
Gadolinium is in the middle of the lanthanide sequence on the periodic table. (The lanthanide sequence is the skinny part at the bottom that, in some periodic tables, is put off to the side.)
Two rows of elements called the "LANTHANIDES" and the "ACTINIDES".
If more elements are discovered in the future, they will be added to the periodic table. New rows will be created in the table to accommodate these elements. The properties and characteristics of these new elements will be studied and used to expand our understanding of the natural world.
Water and chlorine.