The properties of elements are determined by their group/family. Usually, its the area they are located on the periodic table. The valence electrons also determine reactivity, etc.
In order to purify ammonia to high purity, two basic methods are used. The older one consists in passing gaseous ammonia containing 80 ppm of impurities under atmospheric pressure through liquid ammonia with dissolved metallic sodium.
Answer:
Mg + O2 ---> MgO
Explanation: V2O5 + CaS → CaO + V2S5. 5V2O5 + 5CaS → 10CaO + 5V2S5. 3V2O5 + 3CaS → 3CaO + 3V2S5.