Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane
, propanone
and water 
Cost more. Gas and oil have a very steady low price, and also the sun is not always out.
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The first step of the oxidation of a primary alcohol involves conversion to an aldehyde via the elimiination of a hydrogen molecule. Thus, ClCH2CH2CH2OH becomes ClCH2CH2COH, which is 3-chloropropanal.
The type of chemical reaction that the reactants will undergo would be a single displacement reaction.
In a single displacement reaction, one element gets substituted or replaced by another element in a compound. This often leads to the formation of a new compound (aqueous) and a new element (solid or precipitate).
Thus, the complete equation of the reaction becomes:

Cu displaced Ag from AgNO3. Thus Ag becomes precipitated in solution while a new compound, CU(NO3)2 is formed.
More on displacement reactions can be found here: brainly.com/question/13219117