What is hybridization in chemistry, and what are some related topics shown on the chalkboard?

Here's the information from the image:

Definition of Hybridization:

Hybridization is the mixing of two or more orbitals of the same principal quantum numbers to give new sets of orbitals which are exact equivalent of the new orbitals (known as Hybrid orbitals).

Other visible topics on the chalkboard:

• Organic Chemistry
• Homologous Series
• Functional Group
• Saturated and Unsaturated Hydrocarbon