Final answer:
The four smallest alkanes are methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). The four smallest alkenes are ethene (C2H4), propene (C3H6), and butene (C4H8). Drawing these structures requires placing the correct number of hydrogens to satisfy carbon's valency in each molecule.
Step-by-step explanation:
Name and Draw the Structural Formulas
To name and draw the structural formulas for the four smallest alkanes and alkenes, we need to understand the basic chemical structure of these hydrocarbons. Alkanes are saturated hydrocarbons with single bonds between carbon atoms, while alkenes are unsaturated hydrocarbons with at least one double bond between carbon atoms.
Alkanes
Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10
Alkenes
Ethene (also known as ethylene) - C2H4
Propene (also known as propylene) - C3H6
Butene (there are several isomers, but 1-butene is common) - C4H8
Pentene (there are several isomers, but 1-pentene is common) - C5H10, but since the question asked for the four smallest, we will not include it here
Drawing these structures involves writing out the carbon skeleton and ensuring the correct number of hydrogen atoms are present to satisfy the valency of carbon in each hydrocarbon.