Is the ionisation energy of an isolated free atom different from the ionisation energy for the atoms in a crystalline lattice?

If the bandgap between the valence band and conduction band in a material is $5.0 \ eV$, then the material is

The energy gap of silicon is $1.14 \ eV$. The maximum wavelength at which silicon will begin absorbing energy is.....$\mathring A$

The state of the energy gained by valence electrons when the temperature is raised or when an electric field is applied is called as:

The band diagrams for three different semiconductors are shown in the figure below. Starting from the left to the right,identify the types of semiconductors they represent.

The energy band diagrams for three semiconductor samples of silicon are as shown. We can then assert that