# What is periodic table? What is periodic classification?

May 11, 2017

#### Explanation:

The periodic table of the elements is the official way of organizing every element known to us humans by the atomic number. The atomic number is known as the number of protons in that specific element. For example:

Nitrogen: Atomic Number: $7$. Therefore this statement is true:

Statement: Nitrogen's atomic number is $7$, therefore this element has $7$ protons.

Early classifications of the periodic table included, for example, "Newlands' Law of Octaves". Newland found that every eighth element had similar physical and chemical properties.

This quickly developed into something more with Mendeleev's way of sorting the elements. The modern day periodic table however, is organized by the atomic numbers of each element.

Groups and Periods: Groups of elements are also known as "columns". Columns are organized in a specific way too. As you go down the groups on the periodic table, ionization energy and electronegativity decrease. Atomic radius increases as you go down too though. As you go up however, the complete opposite happens.

Periods are known also as "rows". Rows are organized specifically as well. As you go across a period from left to right, ionization energy, electronegativity increase. Atomic radius decreases slowly from left to right on a period. As with "groups", as you go the opposite direction on a "row", energy decreases.

The image above explains a little bit about it. However I will supply you with another link so that any other questions you have, you can explore the website.