Shielding Effect Order and Its Influence - Topic for JEE

The shielding effect is defined as the ability of electrons in an atom to protect one another from the nucleus's pull. It implies that The shielding effect causes the electrons in the valence shell to be withdrawn from the atom more easily. In addition, the more shielding there is, the wider the valence shell can stretch out, and the weaker the attraction becomes. The valence shell is already stretched, and the nucleus can push it much more.

The attraction between an electron and a seat in an atom with more than one electron is known as the shielding effect, also known as nuclear shielding or electron shielding. In addition, the shielding effect causes a decrease in attraction between an electron and a nucleus.

The shielding effect likewise depicts the reduction in the powerful atomic charge on the electron cloud because of the distinction in the powers of fascination on the electrons in the particle. Nuclear fission reaction is a shielding effect exemplified. As in nuclear fission, electrons are pulled away from the atom's centre.

What is the Screening Effect?

In an atom containing a multielectron, the electrons present in the valence shell are attracted towards the nucleus and these electrons are repelled by the electrons which are repelled by the electrons allocated in the inner shell. Due to this, the actual force of attraction between the nucleus and the valence electrons is reduced by the repulsive force which is acting in the opposite direction.

This decrease in the force of attraction exerted by the nucleus on the valence electrons resulting from the presence of electrons from the availability of electrons in the inner shells is known as the shielding effect. The shielding effect occurs between the sublevels between the same principal energy level. An electron in the s sublevel shields electrons present in the p sublevel of the same principal energy level. This is due to the spherical shape of the s orbital.

It can be explained by the shielding effect example of a lithium atom. A lithium atom contains three protons and three electrons. The electronic configuration of lithium is 1s²2s¹, two electrons are present in the first principal energy level and one electron (valence electron) in the second principal energy level. The valence electron is partially shielded by the attractive force of the nucleus by the two electrons present in the inner shell. The removal of the valence electrons becomes easy due to the shielding effect.

Order of Screening Effect

The order of screening effect is s > p > d > f. 

The shielding effect experienced by the outermost electrons increases as the number of electron shells increases. As the screening effect of orbitals reduces from s-orbital to f-orbital in an atom due to the geometry of the orbital.

Effective Nuclear Charge

It is vital to comprehend the shielding effect to determine the effective nuclear charge. The valence electrons are shielded from experiencing the strong pull of the nucleus by the innermost electrons. The central core of an atom is positively charged. Some protons and neutrons are neutrally charged. The equivalent charges show repulsion and inverse charges show attraction.

There are additionally adversely charged electrons around the core in various energy levels. The electrons repulse each other external to the body, where the electrons feel a consistent draw towards the protons in the core. The more prominent the successful atomic charge, the more grounded it is on the furthest electrons towards the core.

Nuclear Charge Formula

The following formula can also be used to compute effective nuclear charge:

Zeff .= Z - S

Where,

Z = Atomic Number 

S = No. of Shielding

Nuclear Shielding and Deshielding

The hydrogen particle applies more noteworthy resistance to the attractive field because of the greater electron thickness around it, making the H molecule resound at a lower recurrence and experience a lower beautiful area, where the H atom peaks in the NMR range. The H atoms are supposed to be safeguarded because of which the H particles are shielding.

This is finished by distinguishing the construction of the particles utilising NMR spectroscopy which is an optimal procedure. Likewise, H particles are encircled by components of some sort. This diminishes the electron cloud reverberating at high radio recurrence and produces a beautiful field called de-shielding.

The Screening Effect of Inner Electrons of an Atom 

A screening effect is caused by screening an atom's inner electrons, which is caused by a drop in ionisation energy. The less energy required to remove an electron from an atom, the better. The greater the number of electrons separating the outermost electron shell from the nucleus. The lower the ionisation energy, the higher the shielding effect. The inner electrons screen the nucleus and the outer electrons' attractive characteristics.

As a result, the screening effect of the inner electrons of an atom causes a decrease in the attraction of outer electrons from the nucleus pull.

Conclusion

Since the force of attraction between the nucleus and the spinning electrons is powerful, and the number of the protons in the nucleus is quite significant in heavy elements, the electrons will either fall towards the middle or move in a spiral path, necessitating the use of a shielding effect. It's also been discovered that the higher the electron shell, the more Shielding affects the outermost electrons.

As a result, the shielding effect diminishes from left to right over time with no change in the group's atomic number, whereas the shielding effect increases from top to bottom.