Learn about the basics of atomic structure in our latest blog post.

 Atomic Structure

According to modern theory, matter is electrical in nature. All materials are made of many tiny particles called atoms. Atom is the basic building block of all materials. An atom consists of a positive charge nucleus in the center around small negatively charged particles, called electrons spinning in a different path or orbit.

 Nucleus:  This is the center of the atom and *contains protons and neutrons. A proton is a positively charged particle, while neutrons have the same mass as a proton, but has no charge. Therefore, the atomic nucleus is positively charged. The number of protons and neutrons is the total atomic weight and is called the atomic weight. It's because the extra particles in the core (i.e. electrons) have negligible weight compared to protons or neutrons.

Orbits (Outer part): It is the outermost part of the atom and contains only electrons. An electron is a negatively charged particle whose mass is negligible. The charge on the electron is equal but opposite to that on protons. Also, the number of electrons is equal to the number of protons in the atom below normal conditions. Therefore, the atom is neutral as a whole. The number of electrons or protons in an atom is called the atomic number.

 The Electron

An electron is a negatively charged particle having negligible mass. Some of the important properties of an electron are :

• Charge on an electron,                                          e = 1.602 × 10−19  coulomb 

• Mass of an electron,                                              m = 9.0 ×  10−31  kg 

 

• The radius of an electron,                                      r = 1.9 ×  10−15meter

• The ratio e/m of an electron  is                     1.77 × 1011 coulombs/kg

This means that the mass of the electron is very small compared to the charge. Due to the nature of the electron, it is very mobile and strongly influenced by electricity or magnetism field.

The energy of an Electron

When an electron is hit by a photon of light, it absorbs the quanta of energy that the photon carries and moves to a higher energy level.

An electron moving around a nucleus has two types: energy ie. kinetic energy due to motion and potential energy due to the charge on the nucleus. The total electron energy is the sum of these two energies. That the energy of an electron increases with distance increase from the nucleus. So, electrons in the second orbit have more energy than the electron in the first orbit; The electron in the third orbit has higher energy than the electron in the second orbit. It is clear that the electron in the last orbit has very high energy compared to the electrons in the inner orbit. These last orbital electrons play an important role in determining the physical, chemical, and electrical properties of a material.

Electrons, therefore, have to jump around in atoms as they gain or lose energy. These properties of electrons, and the energy they absorb or emit, can be put to everyday use.

Structure of Elements

 We have seen that all atoms are composed of protons, neutrons, and electrons. Differences between the various types of elements are caused by differences in the number and arrangement of the particles in their atoms.

The atomic structure can be easily constructed if we know the atomic weight and the atomic number of the element. So take zinc atom case,

Atomic weight = 66

Atomic number = 30

Number of protons = Number of electrons = 30

and Number of neutrons = 66-30 = 36

                                                      

It has 30 electrons arranged in different orbits as follows. That the first orbit will have 2 electrons, the second 8 electrons, the third 18 electrons, and the fourth orbit will have 2 electrons.

Let me know if you have more questions or if there is a specific topic that you would like to know more about.