Chapter 3, Problem 1RQ

Distinguish between the terms electronegativity versus electron affinity, covalent bond versus ionic bond, and pure covalent bond versus polar covalent bond. Characterize the types of bonds in terms of electronegativity difference. Energetically, why do ionic and covalcnt bonds form?

Interpretation Introduction

Interpretation: The terms electronegativity versus electron affinity, covalent bond versus ionic bond and pure covalent bond versus polar covalent bond need to be distinguished. The types of bonds in terms of electronegativity difference need to be characterized. The reason for the formation of ionic and covalent bonds needs to be stated.

Concept introduction: The tendency of an atom to attract a bonding electron pair is termed electronegativity. The amount of energy released in adding an electron to a neutral atom or molecule in the gaseous state leading to the formation of a negative ion is electron affinity. The transfer of one or more electrons to a non-metal from a metal is termed as the formation of an ionic bond while a covalent bond is formed by two electrons shared between two atoms.

To determine: The distinction between the given terms the characterization of the types of bonds in terms of the electronegativity difference. The justification of the formation of an ionic and covalent bond.

Answer to Problem 1RQ

Answer

The required explanations have been rightfully stated.

Explanation of Solution

To determine: The distinction between the terms electronegativity versus electron affinity.

The tendency of an atom in a molecule by which it attracts the electrons towards itself in case of a covalent bond is termed as electronegativity. It is denoted by the symbol X. This was first proposed by Linus Pauling in the year 1932. The measurement of electronegativity is not possible directly and has to be calculated from other atomic or molecular properties.

While the energy change ${\text{(E}}_{\text{initial}}\text{-}{\text{E}}_{\text{final}}\text{)}$ when an electron is added to a neutral atom or molecule in the gaseous sate is known as the electron affinity.

To determine: The distinction between the terms covalent bond versus ionic bond

A type of chemical bond characterized by the sharing of pairs of electrons between the atoms is termed as a covalent bond.

While the ionic bond is one that is formed through the electrostatic attraction between the metal and the non-metal ions.

To determine: The distinction between the terms pure covalent bond versus polar covalent bond

When two atoms having the same electron attracting powers or electronegativities form a covalent bond, this type of bond is termed as a pure covalent bond.

And when two atoms having the different electron attracting powers or electronegativities form a covalent bond, this type of bond is termed as a polar covalent bond. In this case the displacement of the shared pair of electrons toward one of the atoms takes place.

To determine: Characterization of the types of bonds in terms of the electronegativity difference

With respect to the electronegativity difference, the formation of two binds takes place. When the electronegativity difference among the atoms exceeds 1.7, an ionic bond is formed while a covalent bond is formed if this difference is less than 1.7

To determine: The justification of the formation of an ionic and covalent bond energetically.

The formation of these two types of bonds is energetically favored as in these cases the energy of the products is somewhat less than that of the reactants resulting in the stability of the products formed.

Conclusion

The tendency of an atom in a molecule by which it attracts the electrons towards itself in case of a covalent bond is termed as electronegativity. The energy change when an electron is added to a neutral atom or molecule in the gaseous sate is termed electron affinity.

The chemical bond characterized by the sharing of pairs of electrons between the atoms while an ionic bond is formed through the electrostatic attraction between the metal and the non-metal ions

The atoms having the same electron attracting powers or electronegativities a pure covalent bond while the bond formed by two atoms having the different electron attracting powers is a polar covalent bond

With respect to the electronegativity difference, the formation of two binds takes place, ionic and covalent.

The energy of the products is somewhat less than that of the reactants. Hence, the formation of these two types of bonds is energetically favored.