Definition of Electronegativity, Difference from Electron Affinity, Polar and Non Polar Bonds, Separation of Charges and Cause of Polarity -Part 1

Meaning of Non Polar, Polar Bonds and Electronegativity:

Introduction to Electronegativity part 1 video explains answers to all questions listed below :

• What is a nonpolar bond ?
• What s a polar bond ?
• What is a dipole ?
• Definition and  meaning of electronegativity.
• Definition and meaning of electron affinity.
• Difference in electronegativity vs electron affinity ?

Here is the brief summary :

Bond in which there is no charge separation or polarity  is called as non polar Bond like hydrogen molecule(H2)  or Chlorine molecules (Cl2).

 Bond in which there is charge separation or polarity  is called as polar bond like HCl  or HF molecules.

During charge separation due to difference in electronegativity  two poles are created  in the covalent bond -a partial  positive (∂+)and a partial negative (∂-)and is called as a dipole .

Polarity —-> charge separation ——>polar bond ——> dipole 

No Polarity—-> No charge separation —->Non polar bond —->No  dipole 

Hydrogen fluorine bond is a polar bond, nitrogen molecule is non polar  molecule .

Big Question?? Why is there charge separation in polar bonds?

Answer is difference in electronegativity between the bonded atoms.More is the difference in electronegativity, more is the charge separation and more is the polarity.

In Hydrogen fluoride molecule – fluorine is more electronegative than hydrogen so there is charge separation and bond is polar in nature.

Definition of electronegativity:

Electronegativity is the ability of the tendency of an atom to attract shared electrons on itself in a chemical bond .

Definition of electron affinity:

It is the energy released when an electron is added in an isolated gaseous atom.

Basic difference in EN and EA 

Remember-Electronegativity vs Electron affinity 

1. Electronegativity is the tendency and not the energy released or required.
2. Electronegativity operates in chemical bonds and it is not in isolated atoms.
3. Whereas Electron affinity or  the electron gain enthalpy is the energy released when an electron is added in the isolated gaseous neutral atom So units of electron gain enthalpy is in terms of joules or kilojoules
4. Electronegativity  is the tendency so it is not measured in terms of joules or  kilo Joule

Introduction to Electronegativity and Electron affinity -Part 1

Chart of electronegativity  or periodic table of electronegativity based on Pauling scale:

Quiz on Introduction to Electronegativity and Electron affinity -Part 1

 

Results

#1. Increasing order of electronegativity of few elements based on their position in the periodic table is given here Oxygen> Nitrogen >Sulfur >Carbon >Hydrogen >Boron>Magnesium Use above information and pick up the right option of charge separation in the following chemical bonds

A

B

C

D

#2. Which carbon is more EN in the following molecule:                CH3 – CH+ – CH2  – CH3                  

Extreme left carbon

Extreme right carbon

Second carbon from left

Second carbon from right

#3. Basic difference in EN and EA is

1)Electronegativity is the tendency to pull electron density and electron affinity is the energy needed to remove an electron

2) Electronegativity has energy units and electron affinity is measured in in kilo joules

3) Electron affinity is the energy released when an electron added in an isolated atom and electronegativity is the tendency to pull shared pair of electrons in a chemical bond

4) Electron affinity operates on a shared pair of electron in a chemical bond and electronegativity is calculated for isolated gaseous atom

#4. Electronegativity is not measured in in Joules or kilojoules because

It is the energy needed to remove an electron .

It is the energy released when an electron is added in isolated gaseous atom.

It is not an energy but a tendency to pull shared pair of electrons .

It is measured in calories.

#5. Identify the non polar Bond

1

2

3

4

5

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