Potassium arsenide is an ionic compound. This is because potassium is a metal and arsenic is a nonmetal. When a metal and a nonmetal react, the metal will lose electrons to the nonmetal, resulting in the formation of ions. In the case of potassium arsenide, potassium will lose one electron to arsenic, resulting in the formation of K+ and As3- ions. These ions will then combine to form potassium arsenide.