With five, I’m none

Question

A Tyobrien riddle of the week

With two, I flow
With three, I’m one
With four, I move
With five, I’m none

Answer 1

With two, I flow

ac - alternating current flows

With three, I’m one

ace - one spot in cards

With four, I move

pace - a step or movement

With five, I’m none

space - empty region