Hi, I have a question about this problem. How would you find the number of electrons given the charge? It said the answer was 7, but I am confused.

Now total charge on electrons are given in the question.
Charge per electron you can find in the book or on google.
Rest is mathematical dimensional analysis.
Number of electrons = 1.1 *10^-18 Coulombs *  1 electron / (1.602*10^-19) Coulombs
                   Get the answer.