Sunday, 8 December 2019

Atomic Number

  Admin       Sunday, 8 December 2019
Atomic Number - Well, when we talk about the atomic number. The atomic number is nothing but the number of protons in an atom. 

Z= Number of Protons 

Its symbol is Z. Through atomic number one can easily identify the chemical and physical properties of an atom.

Atomic Number

The atomic number also helps in finding out the mass number. To find out the mass of an atom, one needs to calculate the sum of the number of protons and neutrons of that atom.

Atomic Mass =Protons+Neutrons


Atomic Mass = Atomic Number+ Neutrons

Atoms mass is the composition of protons, neutrons, and electrons. In an atom, Electrons have negligible mass. Thus, do not take into account.
  • Protons are located in the nucleus of an atom having a positive electrical charge.
  • Neutrons are situated within the nucleus of an atom having no electrical charge.
  • Electrons are located in clouds outside the nucleolus and have a negative electrical charge.
  • The charge magnitude of Electron and Proton is the same.
  • The overall nucleus has a positive charge.
  • The whole atom is electrically neutral.

While considering various aspects of the atomic number, these particles cannot be neglected because these particles are the main constituents of the atom and have an impact on the behavior/properties of atoms. so that is why we call fundamental particles.

Electron - JJ Thomson
Proton - Goldstein
Neutron- Chadwick
Nucleus -Ernest Rutherford
  • The electrons present around the atom are attracted to the protons.

  • These protons are present in an atomic nucleus.

  • The force with which these electrons are attracted is an electromagnetic force.

  • The protons and neutrons also attract each other in the nucleus. But this force is called the nuclear force.

One thing to consider over here is that certain atoms are present in the periodic table that have the same atomic number but different mass numbers such elements are known as isotopes. such various in atoms allow scientists to use in the treatment of various critical medical conditions.

History Behind Use of Atomic Number

There was an effort to organize the number of elements in the right order. The best outcome later was arranging elements considering the atomic number, not by atomic Mass.

The modern periodic table is based on the atomic number.

Before the invention of atomic number,

Dobereiner number for the element

To study elements in an organized manner, Dobereiner, a German chemist, grouped the elements in triads (groups of three elements), in such a way that

The middle element of the triad had both atomic mass and properties roughly equal to the average of the other two elements of the triad.

Examples: Ca (40), Sr (88), Ba (137): Average of Ca and Ba is equal to= Sr (88.5)
Li (7), Na (23), K (39) : =Average of Li and k is equal to= K (23).

However, this method was soon discarded, since only a few elements known at that time could be arranged in such triads

Newlands Atomic Arrangement

Newland, an English scientist, gave the law of octaves, which states that:

When elements are arranged in increasing order of atomic mass, every eighth element beginning from any element resembles the first element in its physical and chemical properties.

This method was also discarded since it failed to accommodate the heavier elements.

 Dmitri Mendeleev

Dmitri Mendeleev, a Russian chemist published a table of elements, which states that
The properties of elements are the periodic functions of their atomic masses.

Missing Elements
He even predicted the existence of those elements which were not discovered at that time. The whole table arrangement in vertical columns known as groups and horizontal rows are known as periods. He arranged the elements in order of their increasing atomic masses. The table could not explain the trend in atomic mass change. Mendeleev again published a new table of elements that is divided into 4 blocks. This table is called as long-form of a table.

Use of Atomic Number in Periodic Table

Nowadays, scientists are in search of new elements no matter whether they find naturally occur or in the laboratory. The whole world is waiting for New inventions.

All about Atomic Number.


Thanks for reading Atomic Number

« Prev Post

No comments:

Post a comment