Did carbon exist naturally in Earth?

[kindaichi]

I was doing a test on the other day and i came across a question.The question is:

What is the element that cannot exist naturally in Earth?

A.Gold
B.Silver
C.Carbon
D.Sulphur

I choose carbon,but my tuition teacher said he thinks it is sulphur.He wasn;t very sure of his answer though.So,i wonder what it is?What is the answer?

 

[Bystander]

"Native," or natural occurrences, of all four in elemental form are well documented; can you furnish the exact statement of the question?

 

[NoTime]

I read somewhere that it was gold.
Natural in this sense, means that it isn't a significant contsituant of the dust cloud that formed the earth.

I have no idea of the validity of either the claim or the supporting argument.

 

[digital ranger]

if the question was 100% correct

I think gold is the best choice.
It's a rare metal and the most heavy too, so it may have been formed by fusion of other elements.

 

[daveb]

They're all natural elements. Just about every element (except for perhaps the larger trans-uranics) can be produced in a stellar nucleosynthesis, but the half lives of all the transuranics and technetium is small enough for it all to have decayed so that on eart, naturally ocurring elements are all Z less than or equal to 92 (and there isn't any technetium, Z = 43)

 

[Rach3]

Perhaps the question was, which does not exist in pure elemental form? Still, sulfur does exist in elemental deposits:

http://en.wikipedia.org/wiki/Sulfur#Occurrence

 

[kindaichi]

well,to be more exact, my question is which of the four elements cannot exist in the natural state in our earth?

 

[Bystander]

Try rephrasing yourself; don't use "natural state," it isn't too clear what you mean. All four exist as "pure" (uncombined) elements; two, carbon and sulfur appear in more than one allotrope.

 

[interested_learner]

Silver

The question is probably: "Which of these elements can not appear in pure form (meaning not an alloy)." If that is so, the answer is silver. Gold always appears in pure form. Sulfur appears in pure form at the edges of volcanos. Carbon is in pure form in diamonds. Only silver is always an alloy.