the number of protons.
They are put into periods based on their number of electron shells.
It means that elements can be separated by their chemical simulatries as they are on the periodic table of elements.
Atomic Number
All groups in the periodic table contain chemical elements.
The periodic table is based on an element's number of atoms. The elements are arranged from least to most number of atoms.
I can find only two types The Mendeleves Periodic table based on Atomic weight of elements and The Modern Periodic table based on Atomic number of elements.
noble gases or f-block elements
the elements in the modern periodic table are arrange in the increasing order of their atomic numbers.
A Periodic table The Periodic Table of the Elements.
atomic number
Sounds like the Periodic Table of the elements.
The composition of the periodic table is made up of periods and groups. The table arranges the chemical elements based off of their atomic numbers, chemical properties and electron configurations.