When one atom gains an electron some other atom must lose an electron. Ions are always produced in pairs, one positive and the other negative. Since positive and negative charges are attracted they can form an ionic compound, where the compound is held together by these attractions between unlike charges. The most common example is sodium chloride, NaCl. The positive sodium atom is then attracted to the negative chlorine atom and the compound is formed.
Ionic compounds are always neutral.
Some atoms may, however, gain or lose more than one electron. The answers are given below . All ionic compounds dissolve in water and the ions are separted into the solution. Since these ions are able to freely move in the solution they can conduct electricity. Water, which doesn't normally conduct electricity, does conduct electricity when salts are dissolved in it.