The number of
is different for each element and is known as the
number,

Electrons, Atomic Number

Explanation:

The total number of electrons is different for each and every element of the periodic table.

It is known as the atomic number of an element.

Mendeleev's Periodic Table's principle:

The properties of the elements is a periodic function of their atomic mass.

But, this was true only for the lighter elements.

So, the principle of the Long Form of the Periodic Table is:

The properties of the elements is a periodic function of their atomic numbers.

each  column  of the  table  is called a group. elements in a group share similar properties. groups are  read  from  top  to  bottom. metal. metalloid. nonmetal. solid. liquid. gas. fe. hg. o.  2. 3. 4. 5. 6. 7. 8. 9.  2. beryllium. 9.012. 4.  sodium. 22.990.  11. 3.  magnesium. 24.305.  12.  potassium. 39.098.  19. 4.  calcium. 40.078.  20. i guess  i