[leereeves]

If what's being called "charge" here is charge distribution between one side of the element and the other side within the circuit (basically, electrons to the left minus electrons to the right, divided by two lest we count a single moving electron twice), and what's being called "current" here is simply current across the element, then in this case, i = dq/dt.

That's a good mathematical model of the behavior of the elements from a pedagogical perspective, though confusing for more advanced readers.