Noble Gas. Metals have 1 or 2 Valence Electrons. Halogens have 7 Valence Electrons. Semi-Metals can have different amounts.
The method of separating mixtures by means of their differences in the chemical properties of the components is less convenient because these methods requires reactions therefore needs energy, increasing the costs for the process.
Idk it’s making me answer a question in order to get help on my own
