Yes, it is diffusion !
Diffusion is the process in which gas, through random movement of particles, tends to fill up the whole volume of the container in which it is placed. So a similar process would lead the smoke, which is in form of gas (or light particles), to fill in the whole room in which it is contained.
Potassium iodide
Molar mass: 166.0028 g/mol
Formula: KI
Answer:

Explanation:
The charge transferred charge Q= −10nC = -10*10-9 C
Charge of a electron : 
Number of electrons transferred: 