Unit 1 Lesson 4

Question 1

1. Valence bond theory
2. principles of valence bond theory

Answer 1

1. A covalent bond forms when the atomic orbitals of two atoms overlap to share a common region in space and a pair of electrons occupies that region of overlap
2. a. Region of orbital overlap has a maximum capacity of two electrons with opposite spins
   b. There should be a maximum orbital overlap, which creates a stronger more stable bond
   c. To help explain the molecular shapes of some molecules the concept of orbital hybridization is used. This is the combining or mixing of orbitals to produce new orbitals.

Question 2

Molecular orbital theory

Answer 2

When orbitals overlap they combine to form new orbitals called molecular orbitals with new shapes and energy levels

Question 3

Sigma bonds characteristics

Answer 3

Formed by head on overlapping of p or s orbitals
Contains 2 electrons
Cylindrically symmetrical about the axis joining the 2 nuclei.

Question 4

Characteristics of pi binds

Answer 4

Formed by a parallel overlap of two p orbitals
Contains 2 electrons
Less stable than a sigma bond
2nd and 3rd bond