For each of the following bonds, calculate the difference in electronegativity |

Question

For each of the following bonds, calculate the difference in electronegativity |Delta E N|, and give the probable classification of each (ionic, non-polar covalent, polar covalent). In addition, for any bond classified as ionic or polar covalent, give the identity of the atom that would possess the negative charge or partial charge in the bond. What is the difference between the arrangement of electron regions and molecular shape? Under what circumstances will the molecular shape be the same as the arrangement of electron regions? Why must lone pairs be considered when counting electron regions?

Explanation / Answer

1) Electronegativity is a measure of an atom's affinity for electrons. There are following rules to determine whether the bond is ionic, polar or nonpolar.

1. If the electronegativity difference (EN) is less than 0.5, then the bond is nonpolar covalent.

2. If the EN is between 0.5 and 1.6, the bond is polar covalent

3. If the EN is greater than 2.0, then the bond is ionic.

C = 2.55

Na = 0.93

Br = 2.96

O = 3.44

S = 2.58

H = 2.20

F = 3.98

Bond                 EN                    Classification                   negative atom

a) C H               0.35                    nonpolar covalent

b) NaF               3.05                    ionic                                               F

c) FBr                1.18                    polar covalent F

d) OS                 1.5                         polar covalent                             O

2)

When determining the electron regions, lone pairs and bonds are considered and when determining molecular shape only bonded atoms are considered.

For e.g. CH, NH both have four electron pairs about the central atom, so both are sp³ hybridized.

Their orbitals all point about 109° towards the corners of a tetrahedron, so their electron geometry is tetrahedral.

CH has no lone pairs, NH has one lone pair. In CH, the C-H bonds all point towards the corners of a tetrahedron at angles of 109.5°, so the molecular geometry and the electron geometry of CH are each tetrahedral.

In NH, the three N-H bonds point towards three of the corners of a tetrahedron and alone pair towards forth corner. The molecular shape of NH is trigonal pyramidal, but its electron geometry is still tetrahedral.

3) When determining the electron regions lone pairs are counted, because electron geometry depends on it.

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.