Answer
3, 1, 2
Work Step by Step
When two objects come together and experience contact the charges between them must achieve equilibrium.
To get that we use this formula : $ q_{ equilibrium} = \frac{q1 + q2}{2}$
And then we subtract the result from one of the original charges.
$q_{E_{1}} =\frac{(+6e) + (-4e)}{2} = \frac{2e}{2} = 1e$
$6e - 1e = 5e$
$5e$ are transfered
$q_{E_{2}} =\frac{(0) + (+2e)}{2} = \frac{2e}{2} = 1e$
$2e - 1e = 1e$
$1e$ is transfered
$q_{E_{3}} =\frac{(-12e) + (+14e)}{2} = \frac{2e}{2} = 1e$
$14e - 1e = 13e$
$13e$ are transfered
From greatest to lowest electron transfer: 3, 1, 2
