Atomic Number

What is atomic number?

Atomic number is one of the physical quantities given to an atom and it is used to order the atoms existed in earth.

Definition of atomic number:

Atomic number is defined as the total no. of protons present in the nucleus of an atom. It is denoted by the alphabet 'Z'.

Atomic number is also considered for the no. of electrons present in an atom, but the no. of electrons cannot be same in all conditions. When the atom is in atomic state, the no. of protons is equal to the no. of electrons. In this condition, we can take the no. of electrons as an atomic number, but when the atom changes to ionic state, there will be a loss of electrons or gain of electrons. Due to this, the no. of electrons will change, that's why we take no. of protons alone as the atomic number. This is the reason why the atomic number is also known as proton number.

Atomic number - Solution to chaos:

Ancient scientists discovered lot of chemical elements and its combinations, but they name and classify such elements by their physical and chemical properties. There are lot of confusions existed to identify the elements, because the properties of the elements being same for different elements.

The concept of the weight for an atom is found in the period of 300 BC itself. But the table created with the help of atomic weight was first prepared by John Dalton in 1803. However, the confusion still continues when some of the chemicals ordered in the same place.

The modern periodic table prepared by Mendeleev also prepared with the help of atomic weight and the scientist who first enters the concept of number as the category used to prepare periodic table and this number is not an exact atomic number what we study now. However, the controversy still continues to choose the criteria to order the elements in periodic table.

To avoid all of these confusions, the atomic number is the only solution and all this credit goes to Henry Moseley. He numbered the elements based on the concept of atomic number during six month span of time between 1913 and 1914.

He strictly reversed the order that the atomic weight is not the suitable category to prepare the periodic table and the atomic number is the only criteria used to arrange chemical elements.