1. The problem statement, all variables and given/known data Let’s introduce an imaginary atom which can replace the silicon atom and generate one mobile electron. What is electron density when all silicon atoms are replaced by this imaginary atom 2. Relevant equations 3. The attempt at a solution I have tried looking for a formula to determine electron density, but they all look beyond my current understanding. I believe that the answer comes about when solving (electron denisty new)/(electron density silicon) and cancellations occur. I know I don't know much about this, but I am very unsure how to go about this.