When two particles are oppositely charged they attract each other. When they are of the same charge they will repel. The forces of attraction force each other away like two magnets of the same pole (e.g. both North). When two like charges are near each other they will be pushed away from each other. That is, as far as ions are concerned, like charges repel. This principle also helps push electricity in wires by pushing particles away from a region with a lot of the same charge, like the negative pole of a battery.

Source: psych.hanover.edu