Sodium is (like all alkali metals of group 1) far to reactive with oxygen and even water (explosive burning oxidation reaction).
Chlorine is not found in the nature in his elemental form.
Platinum is found in the nature in elemental form.
Calcium is never found in its elemental form in nature.
uranium, caesium, potassium, beryllium, etc.
Phosphorus us found in nature, but in the form of phosphate compounds rather than in pure elemental form. This is because phosphorus is highly reactive and will readily react with oxygen in the air.
Chlorine is not found in the nature in his elemental form.
Sodium is found as a soft solid metal in nature. It is not commonly found by itself, it reacts with things so violently that it is usually found as a compound with other items. Most commonly found is sodium chloride which is just salt. NaCl
combined form
Platinum is found in the nature in elemental form.
Calcium is never found in its elemental form in nature.
Chlorine is not found in its elemental form as chlorine gas, being a halogen, is highly reactive. The most common compound of chlorine is sodium chloride or common salt. This can be found dissolved in sea water.
Sodium is an extremely reactive element, meaning that it is unstable in its elemental form and stable in compounds. It will react spontaneously with oxygen, water, carbon dioxide, and even nitrogen. As a result, it does not naturally occur in elemental form.
Helium has completely filled orbitals. hence it is chemically inert (non reactive) and is found in its pure elemental form.
Occasionally as elemental copper but more often as a sulfide or an oxide.
Yes. helium is found only in elemental form
uranium, caesium, potassium, beryllium, etc.
Sodium exists naturally in compounds, but not in its elemental form. It must be extracted by artificial means.