Each element has its tile or cell in the periodic table.The top row goes with period 6, while the bottom row goes with period 7. These rows of elements, the lanthanides and actinides, are special transition metals. They are placed there because there wasn't room to put them where they should go. There are two rows of elements found below the main body of the periodic table.For example, elements of the halogen group all have a valence of -1 and are highly reactive. Atoms of each element within a group have the same number of electrons in their outermost electron shell. Elements belonging to one of the 18 groups will share similar properties. Each vertical column on the periodic table is called a group.As you move from left to right across a period, elements transitionВ from displaying metal characteristics toward nonmetallic properties. Elements in the same period all have the same electron ground state energy level. There are seven periods on the periodic table. Each horizontal row on the periodic table is called a period.The original table organized the elements by increasing atomic weight. This is the biggest difference between today's periodic table and Mendeleev's periodic table. Every atom of element 118 has 118 protons. Until a new element is discovered, the last element on the table is element number 118. So element number 1 (hydrogen) is the first element.

The atomic number is the number of protons in an atom of that element.

Elements are listed in numerical order by atomic number.

Who arranged the periodic table