|Class 12 Chemistry Isolation of Elements||Occurrence of Metals|
Occurrence of Metals
Elements which have low chemical reactivity or noble metals having least electropositive character are not attacked by oxygen, moisture and CO2 of the air. These elements, therefore, occur in the Free State or in the native state, e.g., Au, Ag, Pt, S, O, N, noble gases, etc.
Highly reactive elements such as F, CI, Na, K, etc., occur in nature combined form as their compounds such as oxides, carbonates sulphides, halides, etc.
Hydrogen is the only non-metal which exists in oxidised form only.