The only two elements in alkenes and alkynes are A. Carbon and Nitrogen B. Carbon and Hydrogen C. Oxygen and Nitrogen D. Oxygen and Hydrogen

B. Carbon and Hydrogen

Explanation:

An alkyne can be regarded as unsaturated hydrocarbon which have at least one carbon—carbon triple bond. They are acyclic aliphatic hydrocarbons, they can be (branched or unbranched) , They have general chemical formula of [ CₙH₂ₙ−2]. One of the compound belonging to this family is Propyne( C3H4) Hence, they contain Hydrogen and Carbon.

Alkenes can be regarded as class of hydrocarbons which posses only carbon and hydrogen, they are unsaturated compounds having least one carbon-to-carbon double bond.

alkenes can also be regarded as "olefins". one of the members of this family is Ethene (C2H4). general formula of alkenes can be written as [C nH 2n],

n=number of carbon atoms present in the molecule

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

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